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Proceedings of Mechanical Engineering Research Day 2017, pp. 381-382, May 2017
__________
© Centre for Advanced Research on Energy
Investigation of the wear characteristics of helical gear using wear debris analysis
A.H.A. Hamid1,2,*, R.M. Dan1,2, N.I. Zulkafli1,2, A. Putra1,2, R.K. Mazlan1,2
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia. 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia.
*Corresponding e-mail: [email protected]
Keywords: Wear characteristic; wear debris analysis; helical gear
ABSTRACT – The focus of this research is to quantify
the wear characteristics of carbon steel helical gear
operating under controlled condition. Helical gears were
tested on a power recirculating gear test rig with loads of
up to 40 Nm and speed of 1000 rpm. Approximately 30
ml of samples were taken at 1 hour intervals. The samples
were analysed using wear debris analysis and oil
analysis. It is discovered that wear can be characterised
accurately using wear debris.
1. INTRODUCTION
Gears are the mechanism to transmit power by two
surfaces that are in contact with each other which are
common in most machines that utilizes mechanical
transmission. Even the most properly designed, well
fabricated, well fabricated and installed gears will
generally experience failure to fatigue of the meshing
surfaces [1]. Wears are vital to be identified and analysed
to estimate the life of the gear. Numerous past research
has focused on the study of wear of the gear utilizing
condition monitoring tools [2-5]. Helical gears are
chosen for the study due to its high load carrying
capacity, high speed transmission and low noise
operation.
The objective of this study is to investigate the
possibility of wear debris analysis to characterise the
wear of the gear.
2. METHODOLOGY
2.1 Helical gear and lubricant specification
The tested helical gears are in a meshing
configuration and the test is conducted at ambient
condition.
Table 1 Helical gear and lubricant specification.
Specification Value
Gear material AISI 4140, Carburize
No. of teeth 35
Helix angle 17.750
Pitch diameter 110.25 mm
Lubricant Dexron III ATF
2.2 Power recirculating gear test rig
The test rig as shown in Figure 1 is constructed to
deliver approximately 40 Nm of load and rotational speed
of 1000 rpm. Torque transducer is installed to ensure the
loading is accurate as possible.
Figure 1 Gear test rig schematics.
Oil sampling were conducted every hour for 80
hours and test were conducted using wear debris analysis
and IR spectroscopy which follows ASTM D7416 and
ASTM D7889 respectively.
3. RESULTS AND DISCUSSION
The result for the wear debris analysis is highlighted
on ferrous content and at significant point in time for the
gear wear as shown in Table 2 to 6 and the type of wear
from the particle shape are generalized [6-8].
From Table 2, platelets of ferrous composition
started to be observed suggesting that rubbing wear
which is an abrasive wear started to occur. Rubbing wear
is expected during the initial surface contact. A smoother
gear is expected and the rubbing wear reaches optimum
condition per time.
From Table 3, needles ferrous particles is observed
which suggests a surface fatigue of fretting occurring.
Fretting wear occurs due to the meshing surface of the
helical gear experiencing cycling load or vibration.
Hamid et al., 2017
382
Table 2 Wear debris analysis at 1st hour.
Conc. Avg. size Shape Comp Severity
Moderate Med 13-40µ Platelets Ferrous Low
Moderate - Platelets Ferrous Low
Moderate - Platelets Ferrous Low
Table 3 Wear debris analysis at 20th hour.
Conc. Avg. size Shape Comp Severity
Moderate Small 6-14µ Platelets Ferrous Low
Few Small 6-14µ Needles Ferrous Low
From Table 4, ribbons ferrous particles suggest that
cutting wear which is an abrasive have started to occur
caused by the gear surface cutting. The presence of
chunks ferrous particles suggests that multiple wear
modes which indicates that a high load or excessive
rotational gear speed. This also indicates that the machine
cycle has entered a steady wear rate.
Table 4 Wear debris analysis at 40th hour.
Conc. Avg. size Shape Comp Severity
Moderate Med 14-40µ Platelets Ferrous Low
Few Small 6-14µ Chunks Ferrous Low
Moderate Fine<6µ Ribbons Ferrous Low
Few Small 6-14µ Needles Ferrous Low
From Table 5, at this stage, chunks particle
concentration has entered a high severity due to
progressive wear caused by the chunks as it becomes
involved in the contact fatigue of the helical gear.
Table 5 Wear debris analysis at 60th hour.
Conc. Avg. size Shape Comp Severity
Few Med 14-40µ Platelets Ferrous Low
Moderate Fine<6µ Ribbons Ferrous Low
Moderate Med 14-40µ Chunks Ferrous High
From Table 6, signs of progressive wear are not
significant due to the machine cycle entering wear
optimum condition. It is noted that the helical gear has no
significant surface wear visible except for minor scuffing
and minor pitting. It is also noted that the cutting wear
and rubbing has decreased or stopped.
Table 6 Wear debris analysis at 80th hour.
Conc. Avg. size Shape Comp Severity
Moderate Med 14-40µ Platelets Ferrous Low
Many Med 14-40µ Chunks Ferrous Low
4. CONCLUSION
The investigative study leads to various results
where it is found that the wear debris analysis can
accurately predict the condition of the machine wear rate
by identifying the particles shape, size, concentration,
composition as well as the severity of the profile. Particle
shape can be utilized to identify the wear mode occurred
to the gear and at the same time could predict the wear
rate profile of the gear. It is observed from the condition
of the experimented gear that it have reached an optimum
wear rate. Thus, the wear of the helical is successfully
characterize through wear debris analysis.
REFERENCES
[1] P.J.L. Fernandes and C. McDuling, “Surface contact
fatigue failure in gears,” Engineering Failure
Analysis, vol. 4, pp. 99-107, 1997.
[2] S. Feng, B. Fan, J. Mao and Y. Xie, “Prediction on
wear of a spur gearbox by on-line wear debris
concentration monitoring,” Wear, vol. 336-337, pp.
1-8, 2015.
[3] V. Fontanari, M. Benedetti, C. Girardi and L.
Giordanino, “Investigation of the lubricated wear
behavior of ductile cast iron and quenched and
tempered alloy steel for possible use in worm
gearing,” Wear, vol. 350-351, pp. 68-73, 2016.
[4] Z. Peng, N.J. Kessissoglou and M. Cox, “A study of
the effect of contaminant particles in lubricants
using wear debris analysis and vibration condition
monitoring techniques,” Wear, vol. 258, no. 11-12,
pp. 1651-1662, 2005.
[5] M. Amarnath and I.R.P. Krishna, “Detection and
diagnosis of surface wear failure in a spur geared
system using EEMD based vibration signal
analysis,” Tribology International, vol. 61, pp. 224-
234, 2013.
[6] D.P. Anderson, “Wear particle atlas,” Naval Air
Engineering Centre, 1982.
[7] B.J. Roylance and M.T. Hunt, “Wear debris
analysis: machine and systems condition
monitoring series,” Coxmoor publishing company,
1999.
[8] B.J. Roylance and S. Raadnui, “The morphological
attributes of wear particles – their role in identifying
wear mechanism,” Wear, vol. 175, pp. 115-121,
1994.
Proceedings of Mechanical Engineering Research Day 2017, pp. 383-384, May 2017
__________
© Centre for Advanced Research on Energy
Electrical conductivity and mechanical properties of graphite/carbon black/carbon nanotube/polypropylene nanocomposites
A. Bairan1,2, M.Z. Selamat1,2,*, S.N. Sahadan1,2, S.D. Malingam1,2, N. Mohamad3
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia. 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia.
3) Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Carbon nanotube; conductive polymer composites; electrical conductivity
ABSTRACT – The properties of conductive polymer
composites (CPCs) can be improved by the addition of
carbon nanotube (CNTs). This research focuses on vary
of composite composition based on polymer matrix and
carbonaceous fillers including Graphite (G), Carbon
Black (CB) and CNTs in order to improve electrical and
mechanical properties of composites according to the
requirement for bipolar plate material stated by the
United State Department of Energy (U.S DOE). It is
found that the effect of small additions of CNTs (5 wt%)
has been increasing electrical conductivity up to 518.9
S/cm while flexural strengths increase from 41.35 MPa
to 61.43 MPa.
1. INTRODUCTION
The use of carbonaceous fillers in the production
of polymer composites to enhance their electrical
properties has attracted considerable industrial attention
because of the high conductivity, low weight, and ease
of processing of these materials, among other
properties[1–3]. Therefore, researches have selected
different reinforcements including carbon fiber (CF),
carbon black (CB), and carbon nanotube (CNTs) to
prepare reinforced composite bipolar plates to meet the
optimum composition for composite bipolar plates [4].
Among these reinforcements, CNTs exhibit the suitable
nanomaterials to fabricate high performance
nanocomposite bipolar plates due to their extraordinary
intrinsic properties [4,5] and relatively low quantity of
loading for the same reinforcing effect [7]. On the other
hand, CB and G have been considered the more
versatile and low-cost fillers for preparing of CPCs
compared to CNTs.
CNTs have the potential to improve the properties
of such highly filled compounds when used in
combination with other filler materials [6]. CNTs
generally form large agglomerates and the biggest
challenge is to disentangle and to disperse the CNTs
agglomerates during the process of melt-compounding
[8]. To incorporate the CNT homogenously distributed
into a polymeric matrix is necessary to achieve high
conductivities of such materials even at low CNTs
content.
The present work is an extension of the work
reported earlier by Selamat et al. [5] with emphases on
effect of CNTs on properties of G/CB/PP
nanocomposites.
2. METHODOLOGY
2.1 Materials
Polypropylene (PP) grade Titan 600 which was
purchased from Polypropylene (PP) Malaysia Sdn. Bhd
used as matrix material. Graphite powder and Carbon
Black powder purchased from Asbury Carbon, New
Jersey was selected as primary and secondary
conductive filler respectively. The third conductive filler
used in this study is Multiwall carbon nanotubes
(CNTs), with grade name: NC7000 (average diameter of
9.5nm, average length of 1.5µm, 90% carbon purity)
from Nanocyl, Belgium.
2.2 Sample preparation
G, CB and CNTs were mixed in a ball mill to get a
homogenous mixture. Then, Rheomix mixer Haake-
Polylab TM with roller type rotors is used and the
material from the previous stage is mixed and the
composition as shown in Table 1. The nanocomposite
obtained by melt compounding was crushed and
pulverized into powders in order to improve
homogeneity of the specimen for next forming process.
A hot press machine was used to shape the samples for
properties measurements. The mixture of all material
was then preheated for 20 min in a mould placed in the
hot pressing machine before it pressed at a temperature
of 185 ºC and a pressure of 85 kg/cm2 for 15 min.
3. RESULTS AND DISCUSSION
From the Figure 1, it shown that the electrical
conductivity of G/CB/CNTs/PP composites increases
initially with increment CNTs content went from 0 wt%
up to 5.0 wt%. But, the electrical conductivity drops
after further addition of CNTs due to agglomeration [4].
The flexural strength increases with the increment
of CNTs content and a maximum flexural strength of
61.43 MPa was obtained at 5 wt.% CNTs as shown in
Figure 2. This phenomena occurs due to the high
Bairan et al., 2017
384
mechanical strength possessed by the CNTs, which
leads to an increase in the flexural strength of the
composite [2]. But, the flexural strength also drops after
further addition of CNTs due to agglomeration [4].
Table 1 The composition of composite G/CB/CNTs/PP
(based on weight %).
Filler Binder
G % CB% CNTs% PP%
55.0 25 0 20
54.0 25 1.0 20
53.0 25 2.0 20
52.0 25 3.0 20
51.0 25 4.0 20
50.0 25 5.0 20
49.0 25 6.0 20
48.0 25 7.0 20
47.0 25 8.0 20
Figure 1 Electrical conductivity of various CNTs
content.
Figure 2 Flexural strength of various CNTs content.
Shore hardness and density results are shown in
Figure 3, where the maximum density occurs at 5 wt.%
CNTs. The addition of CNTs decrease the hardness from
65.1 at 1 wt% to 51.2 at 8 wt.% CNTs. With a greater
addition of CNTs, the hardness drops due to
agglomeration, which leads to a poor hardness [5].
4. CONCLUSION
In summary, the findings provide insights that the
G/CB/CNTs/PP composite with 5wt.% CNTs has
synergistic effect in the electrical conductivity, flexural
strength, bulk density and hardness of the composite
which are exceeded of U.S. DOE requirements.
Figure 3 Shore hardness and density of various CNTs
content.
ACKNOWLEDGEMENT
Grant no.: PJP/2013/FKM(6A)/S01181
REFERENCES
[1] M. Wen, X. Sun, L. Su, J. Shen, J. Li and S. Guo,
“The electrical conductivity of carbon
nanotube/carbon black/polypropylene composites
prepared through multistage stretching extrusion,”
Polymer (Guildf)., vol. 53, no. 7, pp. 1602–1610,
Mar. 2012.
[2] H. Suherman, J. Sahari, A.B. Sulong and N.
Royan, “Electrical Conductivity and Flexural
Strength of Graphite/Carbon Nanotubes/Epoxy
Nanocomposites,” Key Eng. Mater., vol. 447–448,
no. October 2015, pp. 643–647, 2010.
[3] M.Z. Selamat, J. Sahari, N. Muhamad and A.
Muchtar, “The effects of thickness reduction and
particle sizes on the properties graphite -
Polypropylene composite,” Int. J. Mech. Mater.
Eng., vol. 6, no. 2, pp. 194–200, 2011.
[4] A. Bairan, M. Selamat, S. Sahadan and S.
Malingam, “Effect of Carbon Nanotubes Loading
in Multifiller Polymer Composite as Bipolar Plate
for PEM Fuel Cell,” Procedia, vol. 19, pp. 91–97,
2016.
[5] M.Z. Selamat, M.S. Ahmad, M.A. Mohd Daud and
N. Ahmad, “Effect of Carbon Nanotubes on
Properties of Graphite/Carbon
Black/Polypropylene Nanocomposites,” Adv.
Mater. Res., vol. 795, pp. 29–34, Sep. 2013.
[6] M.C.L. de Oliveira, G. Ett and R.A. Antunes,
“Materials selection for bipolar plates for polymer
electrolyte membrane fuel cells using the Ashby
approach,” J. Power Sources, vol. 206, pp. 3–13,
May 2012.
[7] M.C. Hsiao, S.H. Liao, M.Y. Yen, A. Su, I.T. Wu,
M.H. Hsiao, S.J. Lee, C.C. Teng and C.C.M. Ma,
“Effect of graphite sizes and carbon nanotubes
content on flowability of bulk-molding compound
and formability of the composite bipolar plate for
fuel cell,” J. Power Sources, vol. 195, no. 17, pp.
5645–5650, Sep. 2010.
[8] M. Grundler, T. Derieth, P. Beckhaus, A. Heinzel
and F. Cell, “CarbonNanoTubes ( CNT ) in Bipolar
Plates for PEM Fuel Cell Applications
CarbonNanoTubes ( CNT ) in Bipolar Plates for
PEM Fuel Cell Applications,” vol. 78, 2010.
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Proceedings of Mechanical Engineering Research Day 2017, pp. 385-386, May 2017
__________
© Centre for Advanced Research on Energy
Investigation on properties of woven kenaf fiber reinforced polypropylene composite
N.F.M. Zalani1, D. Sivakumar1,2,*, M.Z. Selamat1,2
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Tensile; woven kenaf; natural fiber composite
ABSTRACT – In this study, natural fiber reinforced
thermoplastics composites were fabricated using hot
compression method. The composites were fabricated
with different stacking angle orientation of three layers
of woven kenaf fiber with polypropylene matrix
producing a composite panel with a nominal thickness
of 2 mm. The tensile test was conducted according to
ASTM D3039 using Universal Testing Machine, Instron
model 5969. The results show fiber stacking influences
the tensile strength and strain of the composites.
Hardness and density measurement test also were
conducted to identify physical properties of the
composite samples.
1. INTRODUCTION
Composite materials have been used in aerospace
industries since a long time ago [1]. Composites can be
bonded with metallic alloy to improve the performance
of the materials. The presence of fibres in that laminate
structure can enhance the fatigue life of the structures
[2]. Numerous advantages of natural fiber over synthetic
fiber have caught the attention of most researchers in
the materials field applications, especially in automotive
and aerospace. The high performance of the composite
structure is tremendously being explored due to their
superior mechanical properties which are light weight
and high specific stiffness. There are many other
advantages of using natural fiber instead of synthetic
fiber such as the availability, low cost, light weight, high
specific strength and the most important is
biodegradable [3].
Recently, the thermoplastic-based composites have
become a focus due to the ability of rapid
manufacturing and recyclability advantages compared
to thermoset [4]. The use of natural fiber composites has
increased rapidly due to both economical and
environmentally benefits. Among all the natural fibers
that have been employed in combination with plastics,
kenaf is chosen since they are widely used in this new
century. Also, kenaf is one of the biggest crops that have
high potential to replace tobacco in Malaysia [5]. Kenaf
(Hibiscus Cannabinus) is an annual growth plant which
is in Malvaceae family group. Kenaf plant can grow up
to 12 feet and a type of fast growing plant dependent on
the cultivation, time of planting, harvesting process,
water retting treatments and the processing to get the
fiber [3].
Studies of woven kenaf natural fiber have been
relatively scanty and there are limited studies focusing
on woven kenaf fiber and thermoplastic polypropylene
resin. This present study investigates the tensile
behaviour of the laminated woven kenaf fiber reinforced
polypropylene (kenaf/PP) composite. The effect of three
layers of woven kenaf/PP composite with different
stacking angle orientation of 0°, 45° and various
combinations of the laminate systems were tested and
the failure was analysed.
2. METHODOLOGY
The woven kenaf/PP composite panel consists of
three layers of woven kenaf fiber with different stacking
orientations which are 0°, 45° and combination of both
0°and 45° angle in polypropylene matrix. Table 1 shows
the sample coding and the stacking sequence of the
composite panel produced. The fabrication process
started with the production of PP sheet. Then the orderly
layered woven kenaf fiber was sandwiched in between
PP sheets and placed into a stainless steel picture frame
mould 200×200×2 mm (length×width×thickness). The
laminated structure was compressed using hot press
machine at a temperature of 180℃ and pressure of 50
kg/cm2 for 10 minutes.
Tensile test for kenaf/PP composite was performed
according to ASTM D3039 using Universal Testing
Machine (UTM) Instron model 5969 with a load cell of
50 kN at a speed rate of 2 mm/min. Hardness test was
conducted using shore-D hardness device in accordance
to ASTM D2240 while density test was performed
according to ASTM D792 using densimeter. Three
samples were tested for each orientation to get the
average.
Table 1 Stacking orientation of composite.
Sample Orientation (°)
Polypropylene -
Composite A 0-0-0
Composite B 0-45-0
Composite C 45-0-45
Composite D 45-45-45
Zalani et al., 2017
386
3. RESULTS AND DISCUSSION
Tensile strength is an essential test for a specimen
to test how the material reacts to the applied tension
load and to predict the material engineering
performance. The result shows that for all types of
composite, the tensile strength is better compared to
virgin polypropylene. Figure 1 shows the trend graph of
stress versus strain for woven kenaf/PP composite. It
can be seen that the stress is directly proportional to the
extension until fracture. The graph shows Composite B
has the highest tensile stress with 29.97 MPa. This
might be due to Composite B consist of a combination
of two layers 0⁰ and one layer of 45⁰ fiber angle that
make the composite the strongest among all.
The highest strain indicated by Composite D
which can extend up to 0.053. This might happen due to
angle orientation of fiber which contains all woven
kenaf fiber with 45⁰. Fiber that aligned with 45⁰ angle
experiences trellis effect and is less stiff compare to 0⁰. The phenomena can be seen by referring to the graph
which shows Composite A with all 0⁰ has the lowest
strain value followed by Composite B, Composite C and
Composite D that contain one, two and three layers of
woven kenaf of 45⁰ angle respectively.
Figure 1 Stress-strain graph.
Figure 2 Hardness and density for composite.
Hardness and density results for the tested sample
were analysed and illustrated in Figure 2. Closer
examination of fracture surfaces revealed the fiber
elongates more than PP before fracture which greatly
affect the tensile properties of composite material
compared to virgin PP [6]. Besides, composites give
greater hardness than polypropylene. Composite C is the
hardest among all sample with 19.33 shore-D while PP
has the lowest reading value of hardness with 15.387
shore-D. Furthermore, density measurement test shows
that composites with 45° angle orientation is denser
than 0°. Composite D is the densest with 8.613 g/cm3
since it contains all 45° angle of kenaf fiber while PP
shows the lowest density of only 6.380 g/cm3. Kenaf
woven fiber with 45° angle orientation has higher
mass thus resulted in higher density for fabricated
composite.
4. CONCLUSIONS
The stacking orientation indeed has an effect on
the tensile results. All composite fabricated has a higher
yield and tensile stress, hardness, and density compared
to virgin polypropylene. The overall analysis shows that
Composite D has the highest tensile strain and highest
density among all the composites fabricated while the
highest tensile stress was shown by Composite B and
the hardest composite was demonstrated by Composite
C. The significant of this analysis confirm that the
stacking angle orientation affected the tensile properties
of the composite.
ACKNOWLEDGEMENT
Authors would like to thank Universiti Teknikal
Malaysia Melaka and Ministry of Higher Education for
supporting this research under
ERGS/2013/FKM/TK01/02/07/E00018. Deepest
gratitude to Lembaga Kenaf dan Tembakau Negara for
sponsoring kenaf fiber for this research.
REFERENCES
[1] S. DharMalingam, P. Compston and S.
Kalyanasundaram, “Process variables optimisation
of polypropylene based fibre–metal laminates
forming using finite element analysis,” Key Eng.
Mater., vol. 410-411, pp. 263-269, 2009.
[2] S. DharMalingam, “An investigation into the
forming behavior of metal composite hybrids,”
Ph.D. Thesis, The Australian National University,
Canberra, 2011.
[3] M.A.C. Mahzan. S. DharMalingam, M.H.R.
Hashim, M.R. Said, A. Rivai, M.A. Daud and
Sivaraos, “Effect of Reprocessing Palm Fiber
Composite on the Mechanical Properties,” Appl.
Mech. Mater., vol. 699, pp. 146–150, 2014.
[4] A.N. Kasim, M.Z. Selamat, M.A.M. Daud, M.Y.
Yaakob, A. Putra and D. Sivakumar, “Mechanical
properties of polypropylene composites reinforced
with alkaline treated pineapple leaf fibre from
Josapine cultivar,” Int. J. Automot. Mech. Eng.,
vol. 1, no. 1, pp. 3157–3167, 2016.
[5] M.F.M. Noor, “buletin lktn.pdf,” Lembaga Kenaf
dan Tembakau Negara, p. 7, 2015.
[6] R. Yahaya, S. Sapuan, M. Jawaid, Z. Leman, and
E. Zainudin, “Mechanical performance of woven
kenaf-Kevlar hybrid composites,” J. Reinf. Plast.
Compos., vol. 33, no. 24, pp. 2242–2254, 2014.
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Proceedings of Mechanical Engineering Research Day 2017, pp. 387-388, May 2017
__________
© Centre for Advanced Research on Energy
Fabrication and evaluation of nylon 6 electrospun nanofibre water filtration media for removing suspended solid
N.S.A. Roslan1, A.H. Nurfaizey1,2,*, M.I. Mohamed Hafiz1,2, M.R. Mansor1,2, N.A. Munajat1, Z. Mustafa3
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 3) Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Electrospinning; electrospun nanofibre; filtration; suspended solid
ABSTRACT – Turbidity of river waters due to the
presence of solid suspensions is a real challenge for
many developing countries. This study is about
fabrication and evaluation of nanofibres incorporated
water filters for removing suspended solids. Nylon 6
nanofibres were electrospun onto standard glass fibre
filters. Evaluations were conducted based on BS EN
872 method and a spectrophotometer. The morphology
of the fibres was studied using a scanning electron
microscope and ImageJ software. From the results,
nanofibres incorporated filters exhibited superior
performances compared to standard filters. Findings
from this study are useful for developing new type of
efficient water filters.
1. INTRODUCTION
As in many developing countries, control of water
pollution in Malaysia faces a serious challenge due to
rapid development. Furthermore, residues or wastes
disposed into the river streams from industries could be
incompletely degraded or removed during wastewater
treatment. For example, the increase of solid particles
which remain in suspension in water also known as
suspended solids would be harmful to aquatic life. As a
result, there will be less amount of dissolved oxygen in
water thus fewer living organisms could inhabit the
polluted water [1]. Filter manufacturers are
continuously looking for ways to improve their filtration
technologies including the use of new class of materials.
Submicron-sized fibres could be a potential candidate to
replace fibrous materials used in conventional filtration
medias [2].
Electrospinning is a process for producing
polymeric fibres with submicron-range in diameter
using electric charge [3]. Electrospun nanofibers can be
formed into highly porous mesh with high specific
surface area, good interconnectivity of pores and the
potential to incorporate active materials [4]. These
unique characteristics of electrospun nanofibres make it
desirable for filtration applications. Bjorge et al. [5]
showed that polyamide nanofibre membrane managed
to capture 99.71% of total suspended solid (TSS).
Asmatulu et al. [6] demonstrated that drinkable level of
water could be achieved using nanofibre membranes.
In this study, Nylon 6 electrospun nanofiber
incorporated filters were fabricated and the performance
of the filters was evaluated based on standard TSS
evaluation methods. The knowledge gained from this
study is important for developing new generation of
efficient filtration media.
2. METHODOLOGY
Electrospinning process was carried out using a
laboratory scale electrospinning machine (Model ES1a,
Electrospinz, NZ). Polymer solution was prepared by
dissolving Nylon 6 pellets (Sigma-Aldrich 181110) in
formic acid (Merck 1002642500) to a final
concentration of 20 wt.%. A constant applied voltage of
14 kV was used throughout the electrospinning process
and the electrospinning distance was set at 10 cm.
Standard glass fibre filters with pore size of 1.5 µm and
diameter of 47 mm (Hach Co., USA) were used as the
substrate materials. Incorporation of nanofibres were
done by directly electrospinning nylon 6 fibres onto the
filters. Electrospinning was performed at different
deposition times of 0 (control sample), 2, 4, and 6
minutes. Triplicate samples were prepared for each case
and labelled as sample A, B, C, and D respectively. Two
experiments were conducted using two different
methods i.e. (i) BS EN 872 “Determination of
Suspended Solids” (ii) using a portable
spectrophotometer (Model DR900, Hach Co., USA).
Filters were weighed using four figure balance Model
AG204 (Mettler Toleddo, Switzerland). Wastewater
sample was taken from a water treatment plant at UTeM
Main Campus. Scanning electron microscope (SEM)
Model JSM-5010PLUS/LV (JEOL Ltd., Japan) was
used to examine the morphology of the fibres and
ImageJ software v1.50 (National Institutes of Health,
USA) was used to analyze the SEM micrographs.
3. RESULTS AND DISCUSSION
For BS EN 872 method, the value of total
suspended solid (TSS) retentions were calculated from
the dry weight of the filters before and after filtration
(Table 1). The difference between the values divided by
the amount of water sample for each test gave the
Roslan et al., 2017
388
amount of suspended solids trapped by the filter. TSS
value of the water when using the standard filter
(Sample A – control sample) was 15 mg/L. However, a
steep increase of TSS values were found (TSS 22.4 to
23.9) when using Sample B, C, and D filters (Figure 1).
The results suggest that the addition of nylon 6
electrospun nanofibres significantly improved the
capability of the filters. In addition, a steady increase of
TSS values of Sample B, C, D suggests that there was a
positive trend between filter capability and the amount
of applied nanofibres.
Table 1 Total suspended solid (TSS) retentions using BS
EN 872 method.
Sample A B C D
Electrospinning time (min) 0 2 4 6
Filter weight (before)(mg) 99.6 100.6 100.9 101.1
Filter weight (after)(mg) 101.1 101.9 102.7 102.8
TSS (mg/L) 15.0 22.4 23.0 23.9
Figure 1 TSS retentions of sample A, B, C, and D.
TSS values of the water samples before and after
filtration process using a spectrophotometer are shown
in Table 2. The TSS value was reduced from 18 mg/L to
5 mg/L when using Sample A. The TSS values were
significantly reduced when using Sample B, C, and D
(Figure 2). However, due to the limitation of the device
the actual TSS values were only recorded as ‘Not
Detected’ (ND). The results from both methods suggest
that nanofibers incorporated filters exhibited superior
performances compared to the standard filter.
Table 2 Total suspended solid (TSS) values before and
after filtration using spectrophotometer.
Sample A B C D
Electrospinning time (min) 0 2 4 6
TSS (before)(mg/L) 18 18 20 23
TSS (after)(mg/L) 5 ND ND ND
Figure 2 TSS values after filtration using a
spectrophotometer.
The trapped suspended solids after filtration
process are shown in Figure 3. The average fibre
diameter of the nylon 6 nanofibres was 127.9 nm whilst
the average fibre diameter of the substrate fibres was
744 nm. Further works on characterizing and evaluating
the performance of proposed filters are ongoing and the
results will be reported later.
Figure 3 SEM micrograph (x2000) showing the trapped
suspended solids.
4. SUMMARY
In the first experiment, the addition of nanofibres
onto the filters significantly increased the amount of
trapped suspended solids. In the second experiment,
nanofibres incorporated filters were able to remove
suspended solids from the water samples. The results
suggest that nanofibres incorporated filters have
superior capability compared to a standard filter in
terms of capturing suspended solids. The findings of this
study are important as it could open up new
opportunities for engineering the next generation of
efficient filtration media.
ACKNOWLEDGEMENT
Grant no.: PJP/2015/FKM (2A)/S01397.
REFERENCES
[1] M.A. Gosomji and A.D. Okooboh, “Determination
of the concentration of dissolved oxygen in water
samples from pankshin town to monitor water
pollution,” vol. 3, no. 3, pp. 13–17, 2013.
[2] A.H. Nurfaizey, N. Tucker and M.P. Staiger,
“Functional nanofibers in clothing for protection
against chemical and biological hazards,“ in
Functional Nanofibers and their Applications,
Woodhead Publishing Limited, 2012, pp. 236-261.
[3] N. Hamid, J. Stanger, N. Tucker, N. Buunk, A.
Wood and M. Staiger, “Control of spatial
deposition of electrospun fiber using electric field
manipulation,” J. Eng. Fiber. Fabr., vol. 9, no. 1,
pp. 155–164, 2014.
[4] S. Ramakrishna, K. Fujihara, W.E. Teo, T. Yong, Z.
Ma and R. Ramaseshan, “Electrospun nanofibers:
solving global issues,” Mater. Today, vol. 9, no. 3,
pp. 40–50, 2006.
[5] D. Bjorge, N. Daels, S. De Vrieze, P. Dejans, T.
Van Camp, W. Audenaert, J. Hogie, P. Westbroek,
K. De Clerck and S.W. Van Hulle, “Performance
assessment of electrospun nanofibers for filter
applications,” Desalination, vol. 249, no. 3, pp.
942–948, 2009.
[6] R. Asmatulu, H. Muppalla, Z. Veisi, W.S. Khan, A.
Asaduzzaman and N. Nuraje, “Study of
hydrophilic electrospun nanofiber membranes for
filtration of micro and nanosize suspended
particles,” Membranes (Basel)., vol. 3, no. 4, pp.
375–388, 2013.
14
19
24
A B C D
TS
S (
mg/L
)
Samples
0
2
4
6
A B C D
TS
S (
mg/L
)
Samples
Nylon 6
nanofibre Microfibre of
the substrate
material
Trapped
suspended
solids
Proceedings of Mechanical Engineering Research Day 2017, pp. 389-390, May 2017
__________
© Centre for Advanced Research on Energy
Design and development of a food tray table for commercial aircraft using hybrid composites
A.F.M. Nor1,2,*, M.T.H. Sultan1,2, A. Hamdan1,2
1) Department of Aerospace Engineering, Faculty of Engineering, Universiti Putra Malaysia,
43400 Serdang, Selangor, Malaysia 2) Aerospace Manufacturing Research Centre, Faculty of Engineering, Universiti Putra Malaysia,
43400 Serdang, Selangor, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Hybrid composites; flexural; low velocity impact
ABSTRACT – This research attempted to propose a
newly-developed material, which has natural fiber in
hybrid composites with less sustainability issues. Kenaf
(K) and jute (J) are employed to hybrid with fiberglass
(FB). This research aims to analyze the damage
characteristic from flexural and impact testing at
different layer configuration. Hybrid composites with
four different configurations SP1 (FG-K-J-K-FG), SP2
(FG-K-K-K-FG), SP3 (FG-J-J-J-FG) and SP4 (FG-J-K-
J-FG) are fabricated in the first stage for flexural testing.
In the second stage, two best configurations are
subjected to low-velocity impact at energy levels range
10J to 40J. The results show that SP3 and SP4
configurations possess 90% better mechanical
properties while SP3 shows the best configuration for
impact test.
1. INTRODUCTION
The utilization of composite materials has become
the new alternative as compared to the traditional metals
for some aircraft machine parts mostly due to their
quality increment, durability, resistance from corrosion
and fatigue, and also tolerance towards any kind of
damages. Recently, composites materials are applied
massively in advanced structures [1-4]. In addition,
sustainability and environmental issues had been arising
significantly in the matter of time in order toward less
pollution and greener Earth. Therefore, more extensive
researches had been conducted to promote the efficient
and advanced biodegradable composite materials to
replace existing non-biodegradable synthetic composites
materials at a lower rate and lower cost [1-3,5].
Furthermore, the current researches show that it is
possible for natural fiber as reinforcement materials in
composite due to its good performance and resulting in
an arisen the new era of biocomposites. Their properties
gave competiveness to the other synthetic material in
term of production [6], cheaper, renewable, totally or
partially recyclable and biodegradable [7]. Furthermore,
natural fiber is rapid renewability, long-term
availability, low density and price as well as pleasing
mechanical properties.
Composite materials are applied in many parts in
aircraft. One of the parts is a foldable tray table. The
main problem is the common materials in the
manufacturing of the food tray table are using synthetic
fiber and have a sustainability issues. Therefore, this
project proposes a newly develop hybrid composite in
production of the food tray table and is predicted to
have a less maintainability issues as compared to the
existing one.
2. METHODOLOGY
The experiment is first conducted by fabricating
the specimens with four different configurations of
hybrid composites consisted of fiberglass (FG), jute
fiber (J) and kenaf fiber (K) in the form of woven fiber.
The specimens are fabricated using hand lay-up
technique. Each specimen is consisted of five layers of
each fabricated material by following configuration
respectively as shown in the Table 1.
Table 1 Configuration of 5 layers.
Name Configurations Thickness
SP1 FG – K – J – K – FG 3.15mm
SP2 FG – K – K – K – FG 4.00mm
SP3 FG – J – J – J – FG 1.60mm
SP4 FG – J – K – J – FG 2.10mm
All four configurations of the specimens were cut
using vertical saw machine following ASTM D-790
standard, which is 250mm x 20mm for the flexural test.
The testing had been performed on a flexural testing
machine using the 3-point bending by Instron 3382 with
a capacity of 100kN, with the speed of 1mm/min. Then
the results are compared and analyzed. After that, the
best two configurations are choosing to observe and
compared the damage progression via low velocity
impact test. The new specimens with same best two out
of four configurations are fabricated with different
numbers of layer in order to achieve the thickness
required for the testing.
Then, the fabricated specimen is tested with low
impact velocity for impact test by using Imatek, IM10
Drop Weight Impact Tester, where the impactor will
drop freely from some height. The specimens for impact
test were cut according to Boeing Standard
Specifications, BSS 7260, which is 150mm x 100mm. A
preliminary test is conducted as the pilot test to measure
the highest energy level that material can withstand the
impact energy before full penetration from occur. The
Nor et al., 2017
390
results from the preliminary test show that the highest
energy for both configurations is 40 Joules (J). Then,
increment of 10J from 10J until 40J is chosen in order to
fulfill the observation of damage progression.
3. RESULTS AND DISCUSSION
Figure 1 reports that SP3 shows the highest value
in flexural modulus followed by SP4 composite. The
thickness of the specimen is believed to increase the
strength to withstand bending forces before breaking
point. The detailed result of flexural test is shown in
Table 2.
Figure 1 Flexural stress against flexural strain curve.
Table 2 Data from flexural test.
Specimen Maximum
Load
Flexural
Stress
Flexural
Modulus
SP1 319.77N 120.85MPa 9.16Gpa
SP2 481.61N 144.48MPa 9.92Gpa
SP3 157.56N 230.80MPa 2.50Gpa
SP4 141.03N 163.10MPa 2.05Gpa
High value of flexural modulus indicates that the
material has a high level of stiffness. The SP3 and SP4
composites need higher loads to be elastically deformed
as compared to SP1 and SP2 composites. SP3 and SP4
are selected for low velocity impact test.
Figure 2 Peak impact force-impact energy curve
Figure 2 shows that the average peak impact force
is found to follow the same increasing trend with
respect to impact energy. For comparison, the impact
forces generated for impacts onto SP4 are significantly
larger than SP3 due to its high stiffness. This shows that
SP4 is stiffer than SP3. It can be stated that the greater
the peak impact forces, the stiffer the projectile-to-target
interactions.
4. CONCLUSIONS
The study verified that different configuration with
same number of layers give different mechanical
properties. The results from the flexural test shows it
can be claimed that the best two configurations out of
four are third (SP3) and fourth (SP4) configuration. The
material properties will affect the stiffness of the
structure and the contact stiffness will have a significant
effect on the dynamic response of the structure. In
impact test, the fourth configuration (SP4) has higher
peak load, good impact resistance and a small damage
area. Therefore, the fourth configuration (SP4) has high
strength, slower damage progression and less severe
failure mode compared to the third configuration (SP3).
ACKNOWLEDGEMENT
This work is supported by UPM under GP-IPM
grant, 9415402.
REFERENCES
[1] M.T.H. Sultan, K. Worden, S.G. Pierce, D. Hickey,
W.J. Staszewski, J.M. Dulieu-Barton and A.
Hodzic. “On impact damage detection and
quantification for CFRP laminates using structural
response data only,” Mechanical Systems and
Signal Processing, vol. 25, no. 8, pp. 3135-3152,
2011.
[2] A. Hamdan, F. Mustapha, A.K. Ahmad, A.S.M.
Rafie, M.R. Ishak and A.E. Ismail. “The effect of
customized woven and stacked layer orientation on
tensile and flexural properties of woven kenaf fibre
reinforced epoxy composites,” International
Journal of Polymer Science, vol. 2016, pp. 1-11,
2016.
[3] N. Razali, M.T.H. Sultan, F. Mustapha, N. Yidris
and M.R. Ishak. “Impact damage on composite
structures - A review,” The International Journal
of Engineering and Science, vol. 3, no. 7, pp. 8-20,
2014.
[4] D. Chandramohan and K. Marimuthu. “A review
on natural fibers,” International Journal of
Research and Reviews in Applied Sciences, vol. 8,
no. 2, pp. 194-206, 2011.
[5] A. Chauhan and P. Chauhan. "Natural fibers and
biopolymer," Journal of Chemical Engineering &
Process Technology, vol. S6, pp. 1-4, 2013.
[6] J. Holbery and D. Houston. “Natural-fiber-
reinforced polymer composites in automotive
applications,” JOM Journal of the Minerals,
Metals and Materials Society, vol. 58, no. 11, pp.
80-86, 2006.
[7] A. Bernava, M. Maris and S. Guntis. "Study of
Mechanical Properties of Natural and Hybrid
Yarns Reinforcements," In Advanced Materials
Research, vol. 1117, pp. 231-234. Trans Tech
Publications, 2015.
0
50
100
150
200
250
0 2 4 6
Fle
xura
l st
ress
(M
Pa)
Tensile strain (%)
SP1SP2SP3SP4
0
1
2
3
4
5
6
0 20 40 60
Pe
ak f
orc
e (
kN)
Impact energy (J)
SP3
SP4
Proceedings of Mechanical Engineering Research Day 2017, pp. 391-392, May2017
__________
© Centre for Advanced Research on Energy
Behaviour of hybrid fibers in oil palm shell and palm oil fuel ash reinforced concrete beam
S.M. Syed Mohsin*, M.S. Zainal, G.A. Jokhio, K. Muthusamy
Faculty of Civil Engineering and Earth Resources, Universiti Malaysia Pahang,
26600 Pekan, Pahang Darul Makmur, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Hybrid fibers; lightweight concrete; green structures
ABSTRACT – This paper presents the investigation of
structural behavior of hybrid fibers in oil palm shell
(OPS) and palm oil fuel ash (POFA) reinforced concrete
beam. Four-point bending test was conducted on five
beams with various fiber volume fraction ranging from
0 % to 2.0 %. Based on the results obtained, it was
observed that fibers have the capability to increase the
load carrying capacity, shear strength and ductility of the
beam. Moreover, the crack propagation is lower when the
amount of fiber is increased.
1. INTRODUCTION
Palm oil industries is one of the biggest industry in
Malaysia. Being one of the largest palm oil producers in
the world, the industry continuing generates high solid
waste, for example OPS and POFA. The wastes produced
needs to manage and dispose in appropriate manner that
may contribute to some environmental problems. Thus,
in order to cater these issues, some researcher attempted
to reuse the waste to produce green material, and one of
the way is to replace some of the material in concrete [1-
4]. For instance, the OPS have been used to replace the
aggregate whereas the POFA is used as partial cement
replacement [1-2,4], thus producing a lightweight
aggregate concrete. However, lightweight concrete is a
brittle material. Therefore, in order to add ductility to the
concrete, fibres are added into the concrete mixture. This
is because fibres have the capability to improve the
strength and ductility of the reinforced concrete
structures [3,5].
2. METHODOLOGY
In order to study the structural behavior of hybrid
fibers in OPS and POFA reinforced concrete beam, two
types of fibers, namely kenaf fiber and steel fiber are
mixed into the concrete. The type of steel fiber used is
hooked end with aspect ratio of 120. Whereas, for kenaf
fiber the specification is 30 mm length and diameter in
range 0.5 – 1.5 mm.
The ratio of the fiber is half. Five volume fractions
are considered; 0%, 0.5%, 1.0%, 1.5% and 2.0%
represented in Mix1, Mix2, Mix3, Mix4 and Mix5,
respectively, as shown in Table 1. The coarse aggregate
of the beam is fully replaced with OPS, whereas 20% of
POFA is used to replace the cement. The OPS is sieved
to get the size of 15 mm. Water cement ratio considered
for this study is 0.5. To maintain water cement ratio,
superplasticizer is added as addition of fibers onto the
mixture will reduce its workability.
Table 1 Concrete mix design.
Properties Mix
1
Mix
2
Mix
3
Mix
4
Mix
5
Vf (%) 0 0.50 1.00 1.50 2.00
Water(kg) 18.00 18.00 18.00 18.00 18.00
OPS (kg) 26.00 26.00 26.00 26.00 26.00
POFA(kg) 7.14 7.14 7.14 7.14 7.14
OPC(kg) 29.00 29.00 29.00 29.00 29.00
Sand(kg) 62.00 62.00 62.00 62.00 62.00
SP (kg) 0.60 0.60 0.60 0.60 0.60
Kenaf fiber
(kg) 0 0.25 0.50 0.83 1.08
Steel fiber
(kg) 0 1.52 2.95 4.47 5.99
A square beam of 150 x 150 mm is constructed with
total length of 1500 mm. 3T10 and 2T10 are used for its
tensile and compressive longitudinal reinforcement,
while R6 is used for its shear reinforcement. The loading
arrangement, shear links spacing and dimension of the
beam are given in Figure 1. All the beam is tested on 28th
day.
Figure 1 Loading arrangement and beam dimension.
3. RESULTS AND DISCUSSION
Figure 2 shows the load versus deflection curves of
the tested beams. It can be seen that, as the amount of
fibers increases, the stiffness and the load carrying
capacity of the beam increased as well. The key data
extracted from the load-deflection curves such as Yield
Load (Py) and its deflection (δy), Maximum Load
Carrying Capacity (Pmax) and its deflection (δmax) and
Ultimate Load (Pu) before failure and ultimate deflection
(δu), are summarized in Table 2.
Syed Mohsin et al., 2017
392
Figure 2 Load vs deflection curves.
From the table, it can be seen that the as the fiber
content increases, the strength (Py and Pmax) of the beam
also increase. This is due to the fact that fibers reduce the
rate of crack propagation, and higher forces is required in
order to produce larger crack width. Indirectly, the load
carrying capacity of the beam will also increase. In term
of ductility, μ is ductility ratio obtained by dividing δu by
δy as shown in Table 2. It can be seen that the ductility
ratio of the beam continuing to increase up to 1.5% of
fiber content. This is the limit of the fibers amount of the
beam. After this amount, the ductility ratio is reduced due
to the effect of multiple cracking.
Table 2 Key results from the load-deflection curves.
Properties Mix
1
Mix
2
Mix
3
Mix
4
Mix
5
Vf (%) 0 0.5 1.0 1.5 2.0
Py (kN) 58.40 64.20 70.60 76.10 78.30
δy
(mm) 5.01 5.20 5.23 5.30 5.40
Pmax
(kN) 80.66 83.50 88.70 89.80 94.00
δmax
(mm) 7.20 7.28 73.30 7.38 7.40
Pu
(kN) 78.90 80.50 86.80 88.00 92.00
δu
(mm) 21.60 23.30 25.50 24.00 23.30
μ 4.31 4.48 4.88 4.53 4.32
The load at first crack and cracking pattern of the
beam at failure is shown in Figure 3. Similarly, the values
of the load at first crack is also in upward sequence as the
amount of fibers are increased. For the 1st beam with 0%
fiber, the beam failed in shear-bending mode. Adding
hybrid fibers change the failure mode to a more ductile
one, as the beam now show bending mode of failure.
However, as explained earlier, as the optimum amount of
fibers is observed at 1.5%, the mode of failure now
become bending-shear.
4. CONCLUSION
Hybrid fiber consistently enhances the load
carrying capacity and the ductility of the beam.
Furthermore, the fibers help in slowing the crack
propagation, thus improves the strength of the reinforced
concrete beam. However, sufficient amount of
superplasticizer is needed in order to improve the
workability of the mixture while maintaining the water
cement ratio.
Figure 3 Beam failure mode and cracking pattern.
REFERENCES
[1] P. Shafigh, M.Z. Jumaat and H. Mahmud, “Mix
design and mechanical properties of oil palm shell
lightweight aggregate concrete: A review,”
International Journal of Physical Sciences, vol. 5,
no. 14, pp. 2127-2134, 2010.
[2] K. Muthusamy, Z. Nur Azzimah, N. Ghazali, S.M.
Syed Mohsin and K. Andri, “Compressive strength
and density of oil palm shell lightweight aggregate
concrete containing palm oil fuel ash under
different curing regime,” in Proceeding of
International Conference on Innovations in Civil
and Structural Engineering, pp. 242–247, 2015.
[3] S.M. Syed Mohsin, S.J. Azimi and A. Namdar,
“Behaviour of oil palm shell reinforced concret
beams added with kenaf fibers,” Journal of Applied
Mechanic and Materials, vol. 567, pp 351-355,
2014.
[4] K. Muthusamy and Z. Nur Azzimah, “Exploratory
study of palm oil fuel ash as partial cement
replacement in oil palm shell lightweight aggregate
concrete,” Research Journal of Applied Sciences,
Engineering and Technology, vol. 8, no. 2, pp 150 –
152, 2014.
[5] S.M. Syed Mohsin, M.F. Manaf, N.N. Sarbini and
K. Muthusamy, “Behaviour of reinforced concrete
beams with kenaf and steel hybrid fibre,” ARPN
Journal of Engineering and Applied Sciences, vol.
11, no. 8, pp. 5385 – 5390, 2016.
Proceedings of Mechanical Engineering Research Day 2017, pp. 393-394, May 2017
__________
© Centre for Advanced Research on Energy
Effect of repetitive rework on tensile testing of dissimilar austenitic stainless steel pipes using GMAW orbital welding
S. Laily*, N.I.S. Hussein, M.S. Salleh, M.N. Ayof, T.H. Kean
Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Stainless steel pipe; orbital welding; gas metal arc welding; repetitive rework
ABSTRACT – This study investigates the effect of
repeated repairs welds on the tensile testing of dissimilar
austenitic stainless steel using gas metal arc welding
(GMAW) orbital welding. The weld beads are then
ground away and repair welds are fabricated again by
GMAW. All the samples then cut into dog bone shape
with dimension according to ASTM E8M-04. Then
filling was applied to flatten the gripping sections of each
tensile specimen. Yields strength, ultimate tensile
strength and percentage of elongation were investigated
with maximum 100kN.It is evident from the result that
there increasingly trend of tensile strength only up to
second weld repair, then it started to decrease for the next
weld repair. In this article, the effect of repair welding on
tensile testing of dissimilar stainless steel pipes has been
studied.
1. INTRODUCTION
Orbital welding is the most applicable joining
process in industry whenever high quality of welding
results is desired. Since pharmaceutical equipment
always subjected to high temperature and pressure, they
are more susceptible to premature failure after a certain
service period and it becomes more critical when there is
involvement of dissimilar metal weld joints. This is
because dissimilar metal weld joints have higher
tendency encountered to material degradation such as
thermal aging [1]. Austenitic stainless steels have good
performance in corrosive working environment. This
type of stainless steel is applicable in either conducive or
elevated temperature service environment. Besides that,
they have also good mechanical properties particularly
ductility and toughness, so that it shows remarkable
elongation during tensile testing. Indeed, practice of
DMW with formation of dissimilar metal joint allows the
transition in mechanical properties or in service
conditions as required in certain applications [2].
Repair welding is often desired in industry to
prolong the service lives or enhance performance of the
components. Defects on weldment such as porosity, lack
of penetration, slag inclusion and incomplete fusion may
develop in pipeline fabrication [3]. On the basis of the
comprehensive literature review, the study of repair
welding on dissimilar steel material had rarely been
reported. The main objective is to determine the effect of
repair welding on tensile testing using dissimilar stainless
steel using GMAW orbital welding.
2. EXPERIMENTAL
Setting of equipment to carry out repair welding is
illustrated in Figure 1. The input parameter of welding
machine was arc current 133A and 21V of voltage with
using 70% of argon and 30% of carbon dioxide. With
25mm/min of rotating speed, repair welding was done
until four times. Figure 2 shows turning process for grind
weld bead before followed with repair welding.
Figure 1 1G Position of pipe specimen.
Figure 2 Lathe turning process.
3. RESULTS AND DISCUSSION
Table 1 shows result of tensile testing for base metal
while Table 2 shows result on results for as-welded
specimen and repaired specimens. Every value listed in
the table represented average value of two specimens.
The fractured tensile specimens are shown in the Figure
3.
Laily et al., 2017
394
Table 1 Results of tensile testing for base metals.
Sample
Ultimate
Tensile
Strength
(MPa)
Yield
Strength
(MPa)
Elongati
on (%)
Failure
Location
AISI 304 613.78 310.63 62.00 BM
AISI
316L 612.06 363.13 54.00 BM
By comparison in between two different base
metals, AISI 304 has higher tensile strength than AISI
316L. This is because of its higher carbon content, which
is marked 0.05wt% in extra. Therefore, high carbon
content is responsible to high tensile strength [4].
Table 2 Result for as-welded specimen and repaired
specimen.
Sample
Ultimate
Tensile
Strength
(MPa)
Yield
Strength
(MPa)
Elongation
(%)
Failure
Location
RW0 401.41 240.09 55.00 WM
RW1 470.97 289.82 58.00 WM
RW2 531.91 296.43 63.00 WM
RW3 383.81 260.09 53.50 WM
RW4 330.72 259.30 53.00 HAZ
Figure 3 Fracture tensile specimen after tensile testing.
Figure 3 shows fracture tensile specimen and base
metal after tensile testing. There are two replications for
every repaired samples. While Figure 4 shows graph on
tensile properties versus number of weld repair.
Weld repaired specimens showed an increasing
trend only up to second weld repair, then it is started to
decrease from the next following weld repair. The highest
ultimate tensile strength, yield strength and percent of
elongation for weld repaired samples were observed on
sample RW2 due to the grain growth substantially
affected the tensile strength of weld metal. This is
because coarser grain cannot bear high tensile stress and
crack is usually initiated from coarser grain [5]. After
second repair welding, the grain growth substantially
affected the tensile strength of weld metal. This is
because coarser grain cannot bear high tensile stress and
crack is usually initiated from coarser grain.
Figure 4 Tensile properties vs number of weld repair.
4. CONCLUSION
Tensile testing showed that tensile properties such
as ultimate tensile strength, yield strength and percent of
elongation of weld metal was increased only up to second
repair. This is due to significant grain growth in the
weldment after second repair which facilitated crack
initiation took place. Besides, fracture of tensile
specimens was mostly happened at weldment which had
lowest microhardness. By considering all the factors, it is
suggested that second weld repair is the optimum number
of repair welding.
ACKNOWLEDGEMENT
This research is funded by FRGS Grant numbered
FRGS/1/2015/TK03/FKP/02/F00280.
REFERENCES
[1] A. Aloraier, A. Al-Mazrouee, J.W.H. Price, T.
Shehata, “Weld repair practices without post weld
heat treatment for ferritic alloys and their
consequences on residual stresses: A review,”
International Journal of Pressure Vessels and
Piping, vol. 87, pp. 127-133, 2010.
[2] H. Eisazadeh, J. Bunn, H.E. Coules, A. Achuthan, J.
Goldak, and D.K. Aidun, “A residual stress study in
similar and dissimilar welds,” Welding Research
Journal, vol. 95, pp. 111-119, 2016.
[3] P. Varghese, M.S. Prasad, F. Joseph, M.J. Varkey, K.
Anthony, and A. Sreekanth, “The effect of repeated
repair welding on the corrosion behavior of
austenitic stainless steel and mild steel dissimilar
weldment,” in Proceeding of International
Conference on Advanced in Materials,
Manufacturing and Applications, 2015, pp. 864-
869.
[4] C. Balaji, S.A. Kumar, V.A. Kumar, S.S. Satish,
“Evaluation of mechanical properties of ss 316l
weldments using tungsten inert gas welding”,
International Journal of Engineering Science and
Technology, vol. 4, no. 5, pp. 2053-2057, 2012.
[5] S.G. Wang and X.Q. Wu, “Investigation on the
microstructure and mechanical properties of ti-6al-
4v alloy joints with electron beam welding”,
Materials and Design, vol. 36, pp. 663-670, 2012.
0
100
200
300
400
500
600
700
800
900
1000
RW0 RW1 RW2 RW3 RW4
Str
eng
th [
MP
a]
Number of weld repair
ultimate tensile
strength (MPa)
yield strength
(MPa)
elongation (%)
Proceedings of Mechanical Engineering Research Day 2017, pp. 395-396, May 2017
__________
© Centre for Advanced Research on Energy
Effects of ABS/PC blends ratio towards strength performance R.M.R. Mamat*, M.H. Basir, Z.N. Zakaria, W.M.W. Ibrahim
Faculty of Manufacturing Engineering Technology, TATI University College,
Teluk Kalong, 24000 Kemaman, Terengganu, Malaysia
*Corresponding e-mail: [email protected]
Keywords: ABS; ratio; strength
ABSTRACT – The aim of this study is to analyze the
effect of PC and ABS formulation ratio upon tensile
strength characteristic. A series of three samples
composition of 25, 50 and 75 vol % of ABS product was
prepared by injected together with PC resin and tested
using universal testing machine (UTM). The tensile
strength was measured according to ASTM D-638. The
samples with 25 vol % ABS displayed the highest value
of strength. This is due to proper distribution adhesion
by the ABS and PC. As a conclusion, the higher
composition of PC added to the PC/ABS polymer
resulted in better strength performance.
1. INTRODUCTION
Acrylonitrile-butadiene-styrene (ABS) is a widely
used thermoplastic in polymer industry. In ABS,
acrylonitrile causes an improvement in chemical
resistance and weatherability, while butadiene has the
character of rubber toughness, and styrene offers
glossiness and processability. In PC/ABS blend,
mechanical and thermal properties are improved by PC
while processability, economics and impact resistance
are improved by ABS [1].
In order to upgrade the use and function of ABS,
the simple way is to formulate ABS resin with other
high performance engineering plastics such as
polycarbonate (PC). Mixture of PC and ABS has been
commercially available for a number of years. PC can
contribute towards improvements in strength,
dimensional stability, heat distortion temperature and
impact resistance of the blends. On the other hand, ABS
provides processing advantages, chemical resistance
besides cost reduction with respect to PC.
PC/ABS mixtures have interesting properties that
vary by percent composition of each material. A higher
concentration of PC increases the Young’s Modulus and
results in a higher stress at fracture. Both tensile
strength and Young Modulus increased with increasing
PC content in the ABS/PC [2]. Similar observation was
also reported by Khan et.al (2005) [3], which stated that
tensile strength increased with the increasing PC
contents in ABS/PC blends. Hence, this study is carried
out to determine the optimum formulation ratio of ABS
and PC which contributes to higher strength value of
injected samples.
2. METHODOLOGY
2.1 Material and equipment
The material used in this research work was
summarized as in Table 1.
Table 1 Material Properties from manufacturer.
Polycarbonate, Panlite L-1225Y
Tensile modulus 2400 MPa
Tensile stress 62.0 MPa
Tensile strain 6.00%
Melt Flow Rate 300°C
ABS, TORAY 700-314
Tensile modulus 2700 MPa
Tensile stress 54.0 MPa
Tensile elongation >10%
Melt Flow Rate 220°C
Injection moulding machine: The testing samples
were prepared on TOYO Plastar Injection moulding
machine with technical data shown in Table 2 below.
The shape of specimen sample was prepared according
to ASTM D638 as shown as in Figure 1. Table 3 show
the technical data of UTM was used for testing of
tensile strength properties.
Table 2 Technical data Toyo Plastar Ti-50GX injection
moulding machine.
Name of Machine PLASTAR Ti-50GX
Clamping Force 50 Tonne
Injection Capacity 80cm3
Max Injection Pressure 2500 MPa
Screw diameter 32mm
Table 3 Technical data UTM machine.
Name of
machine
Universal Material Testing
Machine
Brand INSTRON
Max. load 50KN
Max. speed 500 mm/min
Software Series IX
Mamat et al., 2017
396
Table 4 Injection moulding parameter.
Variables Symbol
Actual Value
(coded value)
Low High
Injection Pressure, MPa A 75 (-1) 85 (+1)
Barrel Temperature,°C B 270 (-1) 280 (+1)
Cooling Time, s C 25 (-1) 35 (+1)
Table 5 Blends formulation of materials.
Blends Formulation
PC (wt%) ABS (wt%)
B1 25 75
B2 50 50
B3 75 25
Figure 1 Injected sample according to ASTM D638.
3. RESULTS AND DISCUSSION
Table 6 shows the tensile strength for overall
samples according to design matrix. The details
comparison of tensile strength values for each sample
was summarized by Figure 2.
Table 6 Design matrix with response.
Std Run Factor Tensile strength (MPa)
A B C B1 B2 B3
4 1 75 280 25 49.343 54.461 55.634
8 2 85 280 25 50.845 55.634 53.522
6 3 85 270 35 47.020 47.891 54.390
7 4 75 270 35 51.103 55.165 55.986
1 5 75 280 35 51.666 53.968 54.367
5 6 85 270 25 47.067 52.889 52.795
2 7 85 280 35 52.440 54.179 55.587
3 8 75 270 25 52.018 55.071 52.748
No. of Experiment
Te
nsile
Str
en
gth
(M
Pa
)
87654321
56
54
52
50
48
46
B1
B2
B3
Formulation Ratio
Tensile Strength versus ABS/PC Blends
Figure 2 Graph tensile strength vs ABS/PC blends.
It was observed that the strength decreased with
increasing ABS weight percentage. This is due to ABS
having the rubbery main chain polybutadiene.
According to Krache et.al (2011) [4], by adding some of
ABS content in sampling, the value of strength should
be increase. The scientific explanation to the increment
of the strength was due to the properties of the ABS
where it able to allocate more strong properties as it
dispersed phase in the polymer.
4. CONCLUSION
As conclusion, the higher PC content the higher
the result obtained for the strength which is believed
due to physical properties of the ABS itself. ABS able to
provide good adhesion and bonding between the ABS
and PC resin which lead to good strength distributions
and absorption which proportionally increased the
strength.
REFERENCES
[1] M.M. Raj, “Studies on mechanical properties of
PC-ABS blends,” Journal of Applied Sciences and
Engineering Research, vol. 3, no. 2, 2014.
[2] A. Hassan, and Wong Y. J, “Mechanical properties
of high impact ABS/PC blend,” Simposium
Polimer Kebangsaan, 2005.
[3] M.M.K. Khan and R.F. Liang, “Rheological and
mechanical properties of ABS/PC blends,” Korea-
Australia Rheology Journal, vol. 17, no. 1, pp. 1-7,
2005.
[4] R. Krache and I. Debbah, “Some mechanical and
thermal properties of PC/ABS blends,” Scientific
Research: Materials Science & Applications, vol.
2, pp. 404-441, 2011.
Proceedings of Mechanical Engineering Research Day 2017, pp. 397-398, May 2017
__________
© Centre for Advanced Research on Energy
Study on dimensional accuracy of lattice structure bar using FDM additive manufacturing
M.S. Azmi1, R. Ismail1,2,*, R. Hasan1,2, M.R. Alkahari1,2
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Fused Deposition Modeling (FDM); polymer lattice structure; dimensional accuracy
ABSTRACT – Fused Deposition Modeling (FDM) is a
simple low cost rapid manufacturing technique that
creates part by fusing successive thermoplastic material
layer by layer. However, the capability of FDM to create
accurate parts has been always discussed in many
researches. This paper discusses the dimensional
accuracy of FDM in printing lattice structure. Lattice
structure made using lightweight material such as
Acrylonitrile butadiene styrene (ABS) thermoplastic
material can be used in industry where manufacturing
cost, parts weight and load-bearing capability are
important such as in transportation industry.
1. INTRODUCTION
Current performance of automated devices that uses
battery for its movement is limited due to heavy
sophisticated sensors and body parts[1]. These problem
has caused the device to consume higher energy during
operation. In order to reduce overall weight of a body part
of the automated device, structural properties,
manufacturing technique and material selection must be
continually improved.
Lattice structure is a low density cellular structure
that exist in wide range of things ranging from natural to
human made creation. Lattice structure are favored due
to its better properties of lower density that will
eventually reduce weight of the structure and high
strength to weight ratio when compared to solid bulk
structure and stochastic foam[2]. Lattice structure can be
made using many techniques from conventional
techniques such as injection moulding to additive
manufacturing such as Selective Laser Sintering (SLS),
Selective Laser Melting (SLM) and Fused Deposition
Modelling (FDM).
FDM is one of solid based additive manufacturing
technique that uses lightweight thermoplastic filament as
material. FDM was first invented in early 1990s and
widely used due to its simple, low cost material and
minimum waste that shows a great potential for
fabricating plastic parts for rapid manufacturing
compared to conventional technique[3]. FDM technique
has been widely used ranging from medical treatment,
mould design, automotive and aeronautics[3]. Thus, the
use of FDM technique can reduce manufacturing cost of
parts. Unfortunately, like other rapid manufacturing
techniques, FDM has drawback as the parts made using
FDM are not accurate to the desired dimensions.
Thus, the aim of this paper is to investigate
dimensional accuracy of lattice structure bar in order to
propose a new lightweight body part for application in
small automated device system to extend its operational
hours. This can be done by using lighter weight material
with lower density structure.
2. METHODOLOGY
2.1 Design of lattice structure
The lattice structure is designed using Solidwork
Computer Aided Design (CAD) software with body-
centered-cubic (BCC) topological design as shown in
Figure 1.
Figure 1 Lattice structure design in Solidwork.
The BCC lattice structure unit cell is designed with
length, L= 5 mm and strut to surface angle, =35.26o
angle. The unit cell of BCC lattice structure is shown in
Figure 2.
Figure 2 BCC unit cell.
The drawing is then saved as Solidwork part
document and later converted into. STL file before
inputted into CubePro software for printing.
Azmi et al., 2017
398
2.2 Fabrication of lattice structure Lattice structure specimens are fabricated with
dimension of 160x20x30 mm3 to match industrial part of
an automated autonomous device. The specimens are
fabricated using ABS thermoplastic using CubePro 3D
printer by 3D System Inc. The specimen printing
specifications are as tabulated in Table 1.
Table 1 Specification of specimens.
Strut
diameter
Strength
Pattern
Layer
Thickness
1.2 mm Solid Cross 200 𝜇𝑚
1.6 mm Solid Cross 200 𝜇𝑚
2.0 mm Solid Cross 200 𝜇𝑚
The smallest strut diameter for this study is
fabricated as 1.2 mm, due to the capability of CubePro
3D printer that shows a successful print of strut with at
least 1.0 mm diameter [4].
3. RESULTS AND DISCUSSION
The printed specimens’ strut diameter was
measured using profile projector. Profile projector is a
non-contact measurement device that can measure
sample of variety specimen shapes, size and can measure
accuracy up to 1μm dimension. Profile projector is also
known as shadowgraph because of its working principle
that project the shadow of the sample on the
measurement screen.
Figure 3 Profile projected specimen
The measurements are taken from three different
regions for each specimens and the average printed
diameter is calculated. The data measurements taken are
tabulated in Table 2.
From Table 2, it can be seen that the printed
diameter has about 0.16 mm diameter deviation from the
preset diameter in the drawing for all three specimens.
According to Nancharaiah et al. [5], layer thickness
can affect part accuracy greatly. Bakar et al. [6] also
mentioned that the deviation become worse when
fabricating the circular shape part. As all the specimens
are made with same layer thickness and also with circular
shape strut, the dimensional accuracy deviation of all
three specimens are almost the same.
Table 2 Strut diameter measurements.
Strut
diameter Printed diameter
Percentage
different
1.2 mm 1.045 ± 0.031 mm 12.92 %
1.6 mm 1.434 ± 0.072 mm 10.38 %
2.0 mm 1.842 ± 0.059 mm 7.90 %
4. CONCLUSIONS
FDM is a good manufacturing technique for
fabricating plastic parts due to its lower cost, minimum
waste and lightweight printing material for automated
device body parts. By using lattice structure, the body
parts weight can be further reduced because of its low
density but high strength to weight ratio. However, the
capability of FDM in printing accurate dimension of
lattice structure due to its circular shape strut must be
improved by adjusting the FDM process parameter so
that the deviation from the preset dimension is lower to
acceptable deviation.
ACKNOWLEDGEMENT
The research was supported by research grant
FRGS/1/2016/TK03/FKM-CARE/F00316.
REFERENCES
[1] D. Pebrianti, F. Kendoul, S. Azrad, W. Wang and K.
Nonami, "Autonomous Hovering and Landing of a
Quad-rotor Micro Aerial Vehicle by Means of on
Ground Stereo Vision System," Journal of System
Design and Dynamics, vol. 4, pp. 269-284, 2010.
[2] L. Xiao, W. Song, C. Wang, H. Tang, Q. Fan, N. Liu
and J. Wang, "Mechanical properties of open-cell
rhombic dodecahedron titanium alloy lattice
structure manufactured using electron beam melting
under dynamic loading," International Journal of
Impact Engineering, vol. 100, pp. 75-89, 2017.
[3] J. Wang, H. Xie, Z. Weng, T. Senthil and L. Wu, "A
novel approach to improve mechanical properties of
parts fabricated by fused deposition modeling,"
Materials & Design, vol. 105, pp. 152-159, 2016.
[4] R. Hasan, M. Baharudin, M. Nasarud’din and M.
Alkahari, "Fabrication of polymer lattice structure
using additive manufacturing for lightweight
material," in Proceedings of Mechanical
Engineering Research Day, 2016, pp. 129-130.
[5] T. Nancharaiah, D.R. Raju and V.R. Raju, "An
experimental investigation on surface quality and
dimensional accuracy of FDM components,"
International Journal on Emerging Technologies,
vol. 1, pp. 106-111, 2010.
[7] N.S.A. Bakar, M.R. Alkahari and H. Boejang,
"Analysis on fused deposition modelling
performance," Journal of Zhejiang University-
Science A, vol. 11, pp. 972-977, 2010.
Proceedings of Mechanical Engineering Research Day 2017, pp. 399-400, May 2017
__________
© Centre for Advanced Research on Energy
A techno-economical study on medium density fiberboard using napier grass fiber as ceiling board
Norrahim A. Bakar1,2,*, M. Edyazuan Azni3, M.T.H. Sultan1,2, A. Hamdan1,2
1) Faculty of Aerospace Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
2) Aerospace Manufacturing Research Centre, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 3) Universiti Kuala Lumpur Malaysian Institute of Chemical & Bioengineering, 78000 Alor Gajah, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Napier grass; medium density fiberboard; insulation
ABSTRACT – This project is about extraction of bast
fiber from Napier grass which is known as Pennisetum
purpereum. The purpose of this research is to produce
Medium Density Fiberboard board with density of
350kg/m³ using natural fiber and to investigate the
optimum properties towards the application as ceiling
board. Napier grass fiber board has values resulted at
Modulus of rupture (MOR) is 2.90GPa and Modulus of
elastic (MOE) is 39.03MPa. Water absorption (WA) at
27.83% and thickness swelling (TS) at 6.67% with
thermal conductivity (λ) value is 0.044W/mK. This
fiberboard can be an insulation which contributes to
save production cost, less hazardous, low environmental
footprint and a new innovation.
1. INTRODUCTION
Recently researchers are now on biodegradable
materials as alternative to synthetic materials due to
increasing of environmental issues. Natural fibers are
promising alternative raw materials to be embedded or
substitute the existing in green composite. The
flexibility of the processing, highly specific stiffness,
low cost, renewability, suitability, no impact on global
warming, biodegradability makes the natural fibers have
significant advantages compared with synthetic fibers
[1]. Pennisetum purpureum fiber, also locally known as
Napier grass (Rumput Gajah), is composed of 46%
cellulose, 34% hemicellulose, and 20% lignin [2]. The
objective is to investigate insulation board produced by
using Napier grass as a ceiling board. This is a new
innovation green biodegradable technology.
2. METHODOLOGY
Napier Grass “Pennisetum purpereum” were
collected from a farm located at Sg.Buloh,Selangor.
Three to six month old of Napier grass was used for this
project. The grass was extracted using water retting
process to obtain the bast fiber. Then the bast fiber were
treated using alkali (sodium hydroxide) NaOH solution
of 10% concentration to treat Pennisetum Purpereum
fibers at room temperature and soaking times 6 hours
[3]. Napier grass bast fibers extracted were mixing with
fiber binder PVA (Polyvinyl acetate) in ratio 36% resin
together with 60% solid content Napier Grass Fiber into
mold. The mixtures were hand-formed into
homogeneous single layer mat and pre-cooling. Then
the mixture consequently pressed in a hot press machine
at 175ºC for 5 minutes with pressure of 160kg/cm². Last
stage was drying process and been coated with Gelcoat.
The sample was prepared in dimension 200mm in
length and 200mm in width with thickness 6mm. The
density of fiberboard is 350kg/m³.
The MDF product was investigate accordingly for
thermal and mechanical properties. The mechanical
properties tested following the tensile strength testing
according to ASTM D368-03. From the experimental,
the values modulus of rupture (MOR) and modulus of
elasticity (MOE) are reported. All properties were
calculated from the equations (1) and (2) respectively. (1)
Where Fmax is the maximum load (N), l₁ is the span
(mm), b is the width of the test sample (mm) and t is the
thickness of the test sample (mm).
(2)
Where F₂-F₁ is the increasing load in the range of linear
line of graph (N) and a₂-a₁ is the increasing bending
distance in the range of linear line of graph (N).
Water absorption and thickness swelling according
to ASTM D570-98 was also tested. The percentage of
water absorption (WA) and thickness swelling (TS) are
measured following the standard. The moisture content
of samples is determined by the following the equation
(3).
(3)
Where m1 is mass of sample before drying (g) and m2 is
mass of sample after drying (g).
Thermal conductivity of all board was tested
accordance with the American Society for Testing
Material [4]. The thermal conductivity of a sample is
determined by following the equation (4)
(4)
Where Qu is the output of the upper heat flux
transducer, Ql is the output of the lower heat flux
transducer, D is the thickness of the sample and ΔT is
the temperature difference between the surfaces of the
sample.
Bakar et al., 2017
400
3. RESULTS AND DISCUSSION
3.1 Results for MOE and MOR
The alkaline treatment is for sizing. This treatment
improved the adhesion characteristics by increase the
surface tension roughness and the possibility for
mechanical interlocking and chemical bonding between
the matrixes. These fibers are treated with several alkali
concentrations in 5%, 10%, 15% and untreated. The
effect of fiber to the result obtain is because of the
surface modification has been made by treated to the
NaOH solution for 6 hours. Fiber loading at 0%, 10%,
20%, 30% applied for tensile properties.
Figure 1 Modulus of Elasticity for Napier fiber (MOE).
Figure 2 Modulus of Rupture for Napier fiber (MOR).
The result recorded yield good mechanical
properties for modulus of rupture (MOR) is 2.90Gpa
and modulus of elastic (MOE) is 39.03Mpa at 10%
concentration treatment at 20% fiber loading. The
purpose of treatment to remove hemicelluloses, split the
fiber into fibrils and produce a closely pack cellulose
chain owing to the release of internal strain. It is also
improving the bonding between the fiber-matrix
interfaces.
3.2 Result for water absorption (WA) and thickness
swelling (TS)
According to the data in Table 1, water absorption
for the fiberboard is 27.83% which is the mass for this
fiberboard is 97g after drying. After immersed mass is
124g. This is because improper coating Gelcoat on the
fiberboard surface that course small leaks on the surface
which is percentage moisture content can be absorbed.
The thickness swelling for this Napier grass Fiberboard
is 6.67% after being dried. This is because the fiber
have good matrix bonded between the fibers that gives
good physical properties.
Table 1 Physical properties.
Properties Data (%)
WA 27.83
TS 6.67
3.3 Result for thermal conductivity
The thermal conductivity (λ) values recorded for
this sample is 0.044W/mK. Thermal conductivity values
are numerical values that are determined by experiment.
The higher the value, the more heat is rapidly
transferred through that material. Materials with
relatively high thermal conductivities are referred to as
thermal conductors. Typical value for insulation board
thermal conductivity (λ) is 0.038 W/mk – 0.060 W/mK.
The result show Napier fiber is in between the range of
the insulation board. This is because fiber contain high
cellulose that response as thermal insulation.
4. CONCLUSION
The result indicated that the medium density
fiberboard of Napier grass fiber with density of
350kg/m³ with thickness of 6mm, which bonded by
PVA during hot pressing process have a good physical,
mechanical and thermal properties according to the
standard of insulation board and ASTM C 518. It can be
seen that the board of Napier grass fibers has the
thermal conductivity with the range of 0.0438-
0.0606W/mK which is in range of insulation material.
This shows that the Napier grass is a candidate raw
material for an insulator of particle board for ceiling
board, partition board and other building material for
energy saving [5].
5. ACKNOWLEDGEMENT
This work is supported by UPM under GP-IPM
grant, 9415402.
6. REFERENCES
[1] P.A. Fowler, J.M. Hughes and R.M. Elias,
“Biocomposites: technology, environmental
credential and market forces,” J. Sci. Food
Agric, vol. 86, no. 12, pp. 1781–1789, 2006.
[2] K.O. Reddy, C.U. Maheswari, M. Shukla and
A.V. Rajulu, “Chemical composition and
structural characterization of napier grass
fibers,” Mater. Lett., vol. 67, pp. 35 – 38, 2012.
[3] M.S. Abdul Majid, M. Afendi and S.N.
Aqmariah Kanafiah, “Effects of alkaline
concentrations on the tensile properties of
napier grass fiber,” Appl. Mech. Mater. 2014.
[4] American Society of Testing and Materials.
Standard Test Method for Steady-State
Thermal Transmission Properties by Means of
the Heat Flow Meter Apparatus (C 518), West
Conshohocken, PA 19428-2959, United Stated;
p. 152-166, 2010.
[5] R. Bruce Hoadley Understanding wood: A
Craftmann’s guide to wood technology, United
Stated: Taunton Press; 2005.
Proceedings of Mechanical Engineering Research Day 2017, pp. 401-402, May 2017
__________
© Centre for Advanced Research on Energy
The formation of thermally aged stress corrosion cracking on copper oxide surface under high temperature
G. Omar1,2,*, S.R. Esa3, N. Tamaldin1, N.A.B. Masripan1,2, S. Jasmee1
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
3) MIMOS Semiconductor Sdn. Bhd, Technology Park Malaysia, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Corrosion; copper oxide; interface crack
ABSTRACT – The mechanism of stress corrosion
cracking was investigated on copper surface at various
elevated temperature. The thermally aged copper oxide
was mechanically analyzed by micro indentation and
further investigated by Scanning Electron Microscopy
(SEM) and Transmission Electron Microscopy (TEM)
specifically at the cracked interface. The copper oxide
leads to the formation of thin layer brittle surface
resulting to stress corrosion cracking which is due to the
differences in the diffusion kinetics between copper
oxide and copper causing the formation of micro-voids.
1. INTRODUCTION
Corrosion of copper at elevated temperature can
cause serious reliability issues in semiconductor
packaging. The long-term oxidation at an elevated
temperature leads to corrosion of copper. The corrosion
layer may flake off due to corrosion and surface film
growth [1]. Wan et al, has done the oxidation study of
copper at 800˚C and found that the corrosion products
of copper are easily broken into two layers; the inner
and the outer layers. The outer layer is easy to flake off
from the inner layer as the effect of corrosion [2].
The formation of the flakes is a phenomenon of
Stress Corrosion Cracking (SCC). This is the results of
the interaction of corrosion and mechanical stress
produced a failure by cracking. In engineering material,
SCC is used to describe failures that occur by
environmentally induced crack propagation. In SCC, the
cracks initiate and propagate progressively until the
stresses in the remaining metal exceed the fracture
strength. The process of SCC involved three stages:
a. Crack initiation; small crack forms at some
point of high stress concentration
b. Crack propagation; the crack advances
incrementally with each stress cycle
c. Final failure; occurs rapidly once the advancing
crack has reached a critical size
The contribution of the final failure of the SCC is
insignificant since it occurs rapidly. Crack associated
with SCC always initiates on the surface of a
component at some points of stress concentration. Crack
nucleation includes surface scratches, sharp fillet,
thread, dent and the like. Once the stable crack has
nucleated, it then initially propagates slowly. In metals,
cracks normally extend through several grains during
this propagation stage.
Several mechanisms have been proposed to
explain stress-corrosion interactions that occur at the
crack tip. It is likely that more than one process can
cause SCC. The proposed mechanisms can be classified
into two basic categories: anodic mechanisms and
cathodic mechanisms. That is, during corrosion, both
anodic and cathodic reactions must occur, and the
phenomena that result in crack propagation may be
associated with either type.
2. METHODOLOGY
In this study, a commercial cold work copper alloy
leadframe material was used. The oxidation of the
copper alloy leadframe sample was introduced via a
heat treatment process in an oven under oxygen
environment to promote the oxidation process. The
oxidation temperature was varied at 30°C intervals at
the temperature ranging from 60°C up to 240°C for 3
hours. The surface indentations were carried out using
micro hardness tester. The indentation time was set to 5
seconds for each indentation point. The indentation
mark on the sample surface was imaged using FESEM.
The interface voids were analyzed using Focused Ion
Beam (FIB) and Transmission Electron Microscopy
(TEM).
3. RESULTS AND DISCUSSIONS
3.1 Interface cracking
Figure 1 is the result of micro hardness and SEM
surface imaging. Result shows that despite small
variation of the surface hardness value among the
oxidized samples, there are significant transformation of
the surface properties from ductile metal surface to
brittle metal surface as indicated by the crack formation
on the top surface. This is evidently seen in the sample
that experienced heat treatment temperature of 180°C
and above.
The thin, brittle layer of metal oxide was found
cracked and separated from the base material of copper
that follows the geometry and the perimeter of the
indentation imprint. This is a phenomenon of Stress
Corrosion Cracking (SCC) that the corrosion layers
Omar et al., 2017
402
flake off due to corrosion and surface film growth. The
higher rate of copper oxidation at an elevated
temperature promotes the nucleation, grain growth and a
depleted layer of copper oxide resulting in the formation
of a brittle surface with the interaction of corrosion and
mechanical stress produced a failure by cracking.
Figure 1 Micro indentation micrograph acquired by
FESEM.
3.2 Void formation
The interface layer of copper oxide appeared as a
bright contrast in the bright field TEM image due to the
low density formation of copper oxide resulting in the
development of micro-voids along the interface. Figure
2 is the low magnification of bright field TEM
micrograph that shows the evidence of micro-voids
along the interface of copper to copper oxide. No micro-
voids were observed in the sample that was heat treated
at 150˚C and below. Scattered micro-voids were
observed at the interface region of the sample that was
heat treated at 180˚C and 210˚C. At a higher heat
treatment temperature; 240˚C, the micro-voids start to
initiate the separation in between copper oxide and bulk
copper.
Copper oxide has different diffusion kinetics than
the copper itself. Since the diffusion mechanism
involves lattice vacancies, an atom can move into a
vacant lattice site, effectively causing the atom and the
vacancy to switch places. If large-scale diffusion takes
place in a copper to copper oxide interface, there will be
a flux of atoms in one direction and a flux of vacancies
in the other direction which results in volume defects. In
many metals, voids will form in the oxide film when
oxidized, especially at the metal-oxide interface.
These voids formation, a volume defect, causes the
electron beam to easily transmit during the TEM
imaging process resulting in bright contrast as compared
to intact areas. The micro-voids may cause poor
adhesion in between copper oxide and bulk copper.
Severe effects may be experienced at higher
temperatures since complete separation may occur. In
semiconductor packaging, poor adhesion at this
interface region was found to be the root cause of
delamination issue and product failure.
Figure 2 TEM micrograph on copper oxide interface
voids.
P. Gondcharton et al, in his study on TiN-Cu
bonding also observed a void nucleation and growth at
the bonding interface of TiN-Cu, during post bonding
annealing at the temperature beyond 300˚C [3]. This
phenomenon suggested to the vacancy diffusion due to
thermal stress sustained by copper during post bonding
thermal budget
4. CONCLUSIONS
The copper oxide leads to the formation of thin
layer brittle surface resulting to stress corrosion
cracking. This is due to the differences in the diffusion
kinetics between copper oxide and copper causing the
formation of micro-voids along the interface of copper
to copper oxide. Further increasing the temperature
resulting to the complete separation between base
copper to copper oxide.
REFERENCES
[1] A.E. Segneanu, I. Grozescu, I. Balcu, N.
Vlatanescu and P. Sfirloaga, “A comparative study
between different corrosion protection layers,”
INTECH Open Access Publisher, 2012.
[2] Y. Wan, X. Wang, H. Sun, Y. Li, K. Zhang and Y.
Wu, “Corrosion behavior of copper at elevated
temperature,” Int. J. Electrochem. Sci, vol. 7, pp.
7902-7914, 2012.
[3] P. Gondcharton, B. Imbert, L. Benaissa and M.
Verdier, “Copper-copper direct bonding: Impact of
grain size,” in Interconnect Technology Conference
and 2015 IEEE Materials for Advanced
Metallization Conference, 2015, pp. 229-232.
Severe separation
240˚C
180˚C
210˚C
RT
Micro Voids
Extended Voids
No Voids 180˚C
210˚C
240˚C
RT
Hardness: 135 Hv
Hardness: 137 Hv
Hardness: 143 Hv
Hardness: 147 Hv
Proceedings of Mechanical Engineering Research Day 2017, pp. 403-404, May 2017
__________
© Centre for Advanced Research on Energy
The effect of aluminum thin film thickness on gold wire bond intermetallic formation
G. Omar1,2,*, S.H.S.M. Fadzullah1,2, N. Tamaldin1,2, S.R. Esa3
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
3) MIMOS Semiconductor Sdn. Bhd, Technology Park Malaysia, Bukit Jalil, 57000 Kuala Lumpur, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Intermetallic phases; wire bonding; thin film
ABSTRACT – The rate of intermetallic growth in gold
wire bonding is dependent on the microstructural
properties of the aluminum thin film. The high grain
boundary density of thin film promotes faster
intermetallic growth. All five intermetallic phases (IP)
can be observed in gold aluminum bonding but they
cannot be observed in one particular sample. The
intermetallic phases have different microstructural
properties. The Au2Al has fine and elongated structure,
the Au4Al has fine and equiaxed structure, the Au5Al2
has very fine structure and Au2Al has big structure.
1. INTRODUCTION
Au-Al welding system is the most commonly used
in wire bonding process. However, this bonding system
can easily lead to formation of Au-Al intermetallic
compounds and associated Kirkendall voids [1]. The
formation can be accelerated with the temperature and
time of the operational life. An early study on the
intermetallic compound was performed by Philofsky [2]
that according to him there are five intermetallic
compounds that are all colored: Au5Al2 (tan), Au4Al
(tan), Au2Al (metallic gray), AuAl (white), and AuAl2
(deep purple). Xu [3] has performed similar study but
found another intermetallic phase apart from initial five
intermetallic compounds. The findings on the
intermetallic formation of Au-Al wire bond system is
quite conflicting to each other. Anyone can make a case
for any intermetallic being present and cite his evidence.
This paper studies on the characteristics of and the
microstructural properties of the intermetallic phases
(IP) boned on two different thin film thickness. The
objective is to understand the factors that influenced the
presence of intermetallic phases.
2. METHODOLOGY
In this experiment, the 25 um gold wire were
bonded onto thin film of 2000 nm and 4000 nm. The
samples were thermally aged at 200 ºC. At appropriate
time frame, the samples were taken out and sent for
metallurgical cross sectioning and chemical etched to
investigate the intermetallic phases and microstructural
properties. The elemental composition analysis was
carried out using Energy Dispersive X-ray (EDX)
technique to detect the intermetallic phases.
3. RESULTS AND DISCUSSION
3.1 Effect of thin film thickness on intermetallic
phases
Figure 1 is the result of intermetallic phases of Au-
Al system on 2000 nm and 4000 nm thin film. The
result shows that the all five intermetallic phases (IP)
was observed but not in every specimen. The number of
IP is dependent on the thin film thickness and aging
temperature. The 2000 nm thin film that was aged for
117 hours has two intermetallic phases that are Au5Al2
and Au4Al while the 4000 nm that was aged for 117
hours has four intermetallic phases that are Au5Al2,
Au4Al, Au2Al and AuAl.
Figure 1 The intermetallic formation of 4N gold wire on
two different film thickness that was aged at 200 °C.
Omar et al., 2017
404
This study indicates that the presence of
intermetallic phases (IP) of any sample is dependent on
the materials and the timeframe the sample being
analyzed. The result shows that purple-phase (AuAl2)
for 2000 nm 4000 nm thin film was observed at 5 hours
and 22 hours of thermal aging but totally disappear after
they reach 22 hours and 117 hours respectively. The
2000 nm thin film has minute appearance of Au2Al as
compared to 4000 nm thin film. This is because the
2000 nm thin film has lower supply of aluminum than
the latter. The growth of Au2Al is considerably slow
and being replaced by the AuAl and the rate constant
even becomes negative after long time due to AuAl
nucleating and growing into AuAl2.
The result shows that white-phase (AuAl) only
appeared at aging time of 22 hours and 117 hours for
2000 nm and 4000 nm thin film respectively. This AuAl
phase appeared to have difficulty nucleating initially
and formed in the slow growing AuAl2 at longer times
by excess gold diffusing into it. The white-plague Au2Al
appeared to nucleate slowly but once started, grew at the
second fastest rate.
The predominant phase in all the intermetallic
phases was Au5Al2. This phase nucleated immediately
and grew at fastest rate. At 1316 hours aging time, the
Au5Al2 IP dominating all other phases. This is observed
on of both 2000 nm and 4000 nm thin film. Voids also
appeared in this phase as shown in Figure 2 that
evidently occurred at the gold side of the phases and
were probably caused by the gold diffusing out faster
than the aluminum could replace it. Obviously, cracks
nucleate and grow along this void line in some
specimens. The propagation of the void along the gold
interface was presumably caused by the stresses
generated by thermal expansion differences between the
phases on cooling to room temperature.
The presence of intermetallic phase of Au4Al is in
minute quantity. The only instance when substantial
quantities of this phase were found was when the supply
of aluminum was limited, as behind the voided region
and the Au5Al2 was transformed into Au4Al by the
diffusing gold.
3.2 The microstructural and mechanical properties
of intermetallic phases
Figure 2 is the result of microstructural analysis on
one of the specific sample that has five different
intermetallic phases. The only not observable
intermetallic is AuAl that is difficult to be observed due
to its minute quantity. This result clearly shows that the
intermetallic phases have different microstructural
characteristics.
The Au2Al has a small grain and a columnar structure
pointing in vertical direction. The Au5Al2 is relatively
small grain than the rest of the intermetallic phases and
is in equiaxed structure. The Au4Al has about the same
grain size as the Au2Al but in equiaxed structure. The
AuAl intermetallic phase is the biggest grain size among
the other three intermetallic phases.
The result also shows that the separation of the
intermetallic phases is clearly visible and very well
separated. In this specimen, the small and equiaxed
microstructure of the Au4Al is seen consistently
presence below the gold interface. This is the
intermetallic phases that the void is initiated and
propagated along the gold and Au4Al interface.
Figure 2 The grain structure of intermetallic phases of
Au-Al wire bonding system.
4. CONCLUSIONS
Five intermetallic phases (IP) can be observed in
gold aluminum welding. However not all the
intermetallic phases can be observed in any of the
samples. The presence of intermetallic phases is
dependent on the availability of the material. The
variation in aluminum thin films manipulates different
type of intermetallic phases. The intermetallic phases
have different microstructural properties. The Au2Al has
fine and elongated structure; the Au4Al has fine and
equiaxed structure; the Au5Al2 has very fine structure;
Au2Al has big structure and in addition, all these
structures is relatively smaller than the gold grain
structure.
REFERENCES
[1] H. Xu, C. Liu, C., V.V. Silberschmidt, S.S.
Pramana, T.J. White, Z. Chen and V.L. Acoff,
“New mechanisms of void growth in Au–Al wire
bonds: volumetric shrinkage and intermetallic
oxidation,” Scripta Materialia, vol. 65, no. 7, pp.
642-645, 2011.
[2] Philofsky E., “Design limits when using gold-
aluminum bonds,” in Proceedings 9th Annual
IEEE Reliability Physics Symposium, pp.177-185,
1970.
[3] H. Xu, C. Liu, V.V. Silberschmidt, S.S. Pramana,
T.J. White, Z. Chen and V.L. Acoff, “Intermetallic
phase transformations in Au–Al wire bonds,”
Intermetallics, vol. 19, no. 12, pp. 1808-1816,
2011.
Proceedings of Mechanical Engineering Research Day 2017, pp. 405-407, May 2017
__________
© Centre for Advanced Research on Energy
Weight loss by soil burial degradation of green natural rubber vulcanizates modified by tapioca starch
M. Mazliah1, N. Mohamad1, H.E. Ab Maulod2,*, A.R. Jeefferie1, I.S. Othman1, H. Hanizam2, M.A. Azam1, Q. Ahsan1,
N.M.N. Mohd Safeai2, H. Mohd Mef’at3
1) Carbon Research Technology, Advanced Manufacturing Centre, Faculty of Manufacturing Engineering,
Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 3) Sindutch Cable Manufacturer Sdn. Bhd., Lot 38, Alor Gajah Industrial Estate, 78000 Alor Gajah, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Natural Rubber; tapioca starch; biodegradable
ABSTRACT – The weight loss of soil degraded natural
rubber vulcanizates modified by tapioca starch was
investigated. The samples were prepared by melt
compounding using a Haake internal mixer at different
tapioca starch loading of 0, 5, 10, 20, 40, and 60 phr. The
samples were exposed to soil burial testing for duration
of 7, 14, 21 and 28 days. Then, the weight loss was
measured using the difference in weight before and after
the testing. The mass reduction was observed to be
proportionately increased with the increment of tapioca
starch loadings and prolonged soil burial duration. The
rate of degradations observed was supported with
morphological characteristics of the vulcanizates. This
study is highly significant towards the development of
green natural rubber composites by incorporation of
tapioca starch.
1. INTRODUCTION
To date, there are growing interest in the use of
natural fillers such as starch [1] in rubbers and their
blends. The benefits of these fillers include low cost, easy
availability, sustainable sources and a greener choice to
our environment. Starch is one of the biopolymer
substances most widely found in nature and mostly
consists of amylose and amylopectin. There are several
works of reinforcing elastomers with tapioca starch [2-
3], but only a few addressed the degradation of natural
rubber vulcanizates. Thus, the aim of this study is to
assess the potential utilization of tapioca starch as
biodegradability agent in natural rubber formulations.
This study is part of our research work to produce
biodegradable natural rubber based composites which
proven to have diverse applications from general
household products to engineering components.
2. RESEARCH METHODOLOGY
2.1 Materials
Natural rubber (NR) with commercial trade name of
‘SMR20’ was purchased from Felda Global Ventures
Holdings Bhd (FGV). The NR was masticated using a
two-roll mill for about 10 min at 30 °C prior to
compounding. Carbon black was supplied by Lembaga
Getah Malaysia whereas tapioca starch (TS) was
purchased from Polyscientific Enterprise Sdn Bhd. Other
compounding ingredients such as sulfur, zinc oxide,
stearic acid were purchased from Systerm Classic
Chemical Sdn. Bhd. Tetramethylthiuram disulfide
(Perkacit-TMTD) was purchased from Aldrich
Chemistry, while 6PPD was supplied by Flexys America,
USA. All of the other compounding chemicals were used
as received without further purification steps.
2.2 Sample preparation
The NR was compounded using a Haake internal
mixer working at 60°C and a rotor speed of 60 rpm for 7
minutes according to ASTM D-3192. The TS loading was
varied (Table 1) and the recipe was based on semi-EV
curing [1]. Then, the compounds were subsequently
molded into sheets at 160°C and 150 kgf using a hot press
model GT7014-A from GoTech [4].
Table 1 Formulation recipe used in the preparation of
the composites. Materials Compound (phr)a
Natural rubber 100
Carbon Black 50
Tapioca starch 0 /5 / 10/ 20 / 40 / 60 a Parts per hundred b Tetramethylthiuram disulfide c(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine
2.3 Soil degradation test
Biodegradability of the samples in soils was
measured from percentage weight loss of the samples [5].
In this study, samples prepared in accordance to ASTM
D-412 type C were weighed and buried in natural soil
outdoors, approximately at a depth of 10 cm below the
surface. Five samples were removed every week for
different burial duration of 7 days, 14 days, 21 days and
28 days. After removal, samples were washed in distilled
water and dried at 60°C in a vacuum oven for at least 24
hours. The weight of each specimen was measured before
(W1) and after (W2) degradation. The weight loss (WL)
was calculated using Equation 1.
Mazliah et al., 2017
406
𝑊𝑒𝑖𝑔ℎ𝑡 𝐿𝑜𝑠𝑠 (𝑊𝐿) = 𝑊1− 𝑊2
𝑊1 𝑥 100 (1)
3. RESULTS AND DISCUSSION
3.1 Weight loss
Figure 1 depicts the degradation rate experienced by
NR vulcanizates for the effects of tapioca starch loading
and soil exposure time. From the results, both factors
played significant roles. The samples exhibited
pronounced lost in their weight once exposed to almost 2
weeks to the soil degradation which shown by drastic
change in the curve. The rate of the degradation started at
very low rate of almost 0 %/day to upto 0.21 %/day for
sample with 60 phr tapioca starch. The rate of
degradation was dramatically increased beyond this point
and in some formulations the curve manifested a constant
change until 28 days. The degradation rate was
accelerated with the amount of tapioca starch present in
the samples. It was noted that weight loss was highly
proportional to the starch content. As the samples
exposed to the moistures, heat and microbes in the soils,
the hydrophilic portions of the starch will be degraded,
consumed and depicted as weight loss. Therefore, the
degradation process of a natural polymer such as tapioca
starch is highly complex which involved both climate and
biology elements. During the soil burial test, the starch
structure is destroyed and the amylopectin and amylase
chains degraded [6].
Figure 1 Percentage of weight loss versus time of NR
vulcanizates modified by tapioca starch for soil burial
degradation test.
3.2 Surface morphology
The degradation experienced by samples were
explained by the morphological characteristics of the
samples exposed to the soil burial testing. Figure 2 shows
the morphologies of three selected samples before and
after the testing at 500X magnifications via optical
microscopy. From the morphology, the white phase is
recognized as dispersed tapioca starch in the natural
rubber matrix which clumped together during the
compounding process. The starch aggregated into larger
particles as the loading of starch increased in the samples.
The starch aggregates appear smeared with larger sizes in
vulcanizates after soil burial testing of 28 days. This was
due to the swollen starch particles from reactions with
microbes, moistures and other factors in soil. Presence of
water promotes the microbe activities which results in
molecular degradation of the vulcanizates. The biological
degradation process form microbe’s enzymes could
occur under aerobic and anaerobic conditions, leading to
complete or partial removal of components to
environment [7].
4. CONCLUSION
As the conclusion, it was found that rate of
degradation of natural rubber vulcanizates is highly
influenced by the loading of tapioca starch into the
matrix. Nevertheless, the degradation curves nearly
achieved their constant rates after almost 2 to 3 weeks of
exposure to soils. This demonstrates the promising
potential for sustainable mechanical properties and
confirms the biodegradability tendency once in contact
with soils. The findings are significant to be exploited for
future green rubber composites based products.
Figure 2 The comparison of morphology for before and
after exposed to soils for 28 days.
ACKNOWLEDGEMENT
The authors acknowledge the UTeM for funding under
the project number of PJP/2016/FKP/HI6/S01484.
REFERENCES
[1] M. Mazliah, N. Mohamad, A.R. Jeefferie and H.E.
Ab Maulod, “cure characteristics and tensile
properties of natural rubber vulcanizates modified
by tapioca starch,” in Proceedings of Mechanical
Engineering Research Day 2016, 2016, pp. 163-
164.
[2] A.W.M. Kahar and H. Ismail, “High-density
polyethylene/natural rubber blends filled with
thermoplastic tapioca starch: Physical and
isothermal crystallization kinetics study,” J Vinyl
and Additive Technology, vol. 22, no. 3, 2016.
[3] S. Attharangsan, H. Ismail, M. Abu Bakar and J.
Ismail, “Carbon black (CB)/rice husk powder
(EHP) hybrid filler-filled natural rubber
composites: Effect of cb/rhp ratio on property of the
composites,” Polym Plast Technol Eng, vol.51,
no.7, pp.655–662, 2012.
Mazliah et al., 2017
407
[4] A.R. Jeefferie, S.H. Ahmad, C.T. Ratnam, M.A.
Mahamood and N. Mohamad, “Effects of PEI
adsorption on graphene nanoplatelets to the
properties of NR/EPDM rubber blend
nanocomposites,” J Mater Sci, vol. 50, pp. 6365 –
6381, 2015.
[5] Y.H. Lum, A. Shaaban, N.M.M. Mitan, M.F. Dimin,
N. Mohamad, N. Hamid and S.M. Se,
“Characterization of urea encapsulated by
biodegradable starch-PVA-glycerol,” Journal of
Polymers and the Environment, vol. 21, no. 4, pp.
1083-1087, 2013.
[6] N.I. Miren, A. Carmen, H. Marianella, G. Jeanette
and P. Jenny, “Characterization of natural
rubber/cassava starch/maleated natural rubber
formulations,” Revista Latinoamericana de
Metalurgia y Materiales, vol. 31, no. 1, pp.71-84,
2011.
[7] K. Leja and G. Lewandowicz G, “Polymer
biodegradaion and biodegradable polymers – A
review,” Polish Journal of Environmental Studies,
vol. 19, no. 2, pp. 255 – 266, 2010.
Proceedings of Mechanical Engineering Research Day 2017, pp. 408-409, May 2017
__________
© Centre for Advanced Research on Energy
Synthesis of TiO2 powders with addition of (NH4)2SO4 for cold spray coating
A.R. Toibah1,2,*, M. Yamada1, M. Fukumoto1
1) Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Department of Mechanical Engineering, Toyohashi University of Technology, 1-1, Tempaku-cho,
Toyohashi, Aichi, 441-8580, Japan
*Corresponding e-mail: [email protected]
Keywords: Titanium dioxide; hydrolysis; cold spray coating
ABSTRACT – In this work, a simple hydrolysis
process has been employed to synthesize anatase TiO2
using titanyl sulphate; TiOSO4 with the addition of
ammonium sulphate; (NH4)2SO4 as starting materials
for cold spray process. SEM images revealed that higher
mol addition of (NH4)2SO4 into the precursor promotes
the formation of agglomerates of primary and secondary
particles of TiO2 powder. However, there are no
significant changes in terms of crystallinity as shown by
XRD patterns. A preliminary study on coating
deposition using cold spray showed that TiO2 powders
can be deposited onto the ceramic tile substrate.
1. INTRODUCTION
Of the several factors contributing to successful
ceramic coating formation during the cold spray
process, feedstock powder, in particular, stands out as
shown by several studies that have been conducted [1-
2]. Plastic deformation, which is required for powder
deposition using cold spray method, can occur in
ceramic material when the feedstock materials are in
nanosized particles [3]. The used of nanoparticle
powder for cold spray can promote ductility in the
powder by having a better capacity for the sliding of
small grains over each other and it is believed to be a
factor that help build up the coating when using ceramic
as feedstock material [4]. For a cold spray process, the
feedstock powder should be in the microsized range as
to avoid the powder clogging inside the feeding system
that transports the particles from the powder feeder to
the nozzle [2]. Moreover, due to a safety and
environmental regulations issue, the handling of fine
particles during spraying requires more safety
precautions than with the handling of coarser particles
[4]. Usually nanosized powders were agglomerated up
to submicron sized by means of a spray drying process.
However, spray-drying process that used to agglomerate
the fine particles into microsized range particles might
contribute to the loss of the nanosized grains especially
after the heat exposure during the sintering process.
Therefore, other alternative methods to prepare powder
feedstock materials for cold spray coating are crucial to
preserve the properties of the original properties of the
feedstock powders. In this paper, anatase TiO2 powders
in agglomerated form were synthesized by hydrolysis
method. The effect of the addition of (NH4)2SO4 during
the synthesis on microstructure and crystallinity of the
obtained powders were investigated. Coating deposition
using the synthesized powders were also conducted.
2. METHODOLOGY
The hydrolysis reaction was performed using 10
wt. % of TiOSO4 as the precursor for TiO2 and distilled
water. During the hydrolysis, 0.1, 0.5 & 1 mol% of
(NH4)2SO4 was added. The solution was stirred on a hot
plate to hold the temperature of the solution at ~80 °C
for 8 h. Upon completion the synthesis, a white
precipitate was formed. The precipitate was washed
with distilled water several times and then dried in an
oven to obtain a powder. As a comparison, a reference
TiO2 powder without the addition of (NH4)2SO4 was
performed with the same procedure.
A CGT Kinetiks 4000 cold-spray system was used
to deposit the coating using as-synthesized TiO2 powder
onto the ceramic tile substrate. The process gas
temperature and pressure used were 500°C and 3 MPa,
respectively. Nitrogen was used as the process gas in
this experiment.
The XRD patterns were obtained using a Rigaku
RINT 2500 with Cu-Kα radiation (λ = 1.5406 A) over
the 2θ range of 20-80°. The morphology of the resulting
powders and the obtained fractured cross sections of the
coating samples were examined using a Field Emission
Scanning Electron Microscope (FESEM: SU8000,
Hitachi).
3. RESULTS & DISCUSSION
Figure 1 shows the SEM image illustrating the
morphology of the TiO2 powders obtained from 0-1
mol% (NH4)2SO4 addition during the synthesis process.
The results show that the simple synthesis method can
produce powders that readily agglomerate the nano-
sized primary particles to micro-sized feedstock
powders for the cold spray process. Moreover, it is
clearly evident from the SEM image that the TiO2
powders that synthesized without the addition of
(NH4)2SO4 seem highly porous, where big pores were
observed and pointed out by arrows in Figure 1 (b). The
results also show that more spherical profile with more
pronounce of small agglomerates (secondary particles,
2°) inside larger agglomerates (tertiary particles, 3°)
with denser particle packing was obtained and more
Toibah et al., 2017
409
visible in the TiO2 powders which synthesized with the
addition of (NH4)2SO4.
Figure 1 SEM images of the TiO2 powders synthesized
with different mol% addition of (NH4)2SO4 at
magnifications of 5000 and 30 000, respectively:
(a & b) 0 mol%, (c & d) 0.1 mol%, (e & f) 0.5 mol%,
and (g & h) 1 mol%.
Figure 2 XRD pattern of as-synthesized TiO2 at
different mol% addition of (NH4)2SO4: (a) 0 mol%, (b)
0.1 mol%, (c) 0.5 mol%, and (d) 1 mol%.
However, no significant difference in crystallinity
can be observed when the TiO2 powders were
synthesized with different mol% addition of (NH4)2SO4
as shown by the XRD patterns in Figure 2. The patterns
show the characteristics of the anatase phase of TiO2
and are in good agreement with PDF card No. 21-1272.
The preliminary study of coating formation
depicted that the powder obtained could be used as the
feedstock powder for cold spray process to make
coating as it can be deposited onto the ceramic tile
substrate as shown in Figure 3. This study showed that
addition of (NH4)2SO4 during powder synthesis
provides denser microstructure of agglomerated TiO2
powders which produce a thicker coating compared to
the powder synthesized without the addition of
(NH4)2SO4 as shown in Figure 3 (b). Addition of
(NH4)2SO4 during the synthesis has produced
agglomerated powders with less porosity and tightly
bonded particles which lead to better particle impact
onto the substrate which help to build up the coating.
Moreover, details observation of the surface and cross-
sectional views of cold sprayed TiO2 coating which
synthesized with 1 mol% addition of (NH4)2SO4 shows
that the coatings composed of small TiO2 particles in the
size of <20 nm as shown on Figure 3 (c) and (d),
respectively.
Figure 3 Cross-sectional view of TiO2 coating deposited
by cold spray process: (a) without addition of
(NH4)2SO4 (b) 1 mol% addition of (NH4)2SO4 (c)
surface of coating and (d) cross-section of coating.
4. CONCLUSION
This study investigated the influence of addition of
different mol % of (NH4)2SO4 to promote agglomeration
of TiO2 that synthesized by simple hydrolysis method
for cold spray process. The study showed that
agglomeration of TiO2 powders can be promoted even at
lower percent of addition of (NH4)2SO4; 0.1 mol%. This
method is capable to produce an organize structure of
microsized agglomerated powders which were desired
for cold spray process.
REFERENCES
[1] N.T. Salim, M. Yamada, H. Nakano, K. Shima, H.
Isago and M. Fukumoto, “The effect of post
treatments on the powder morphology of titanium
dioxide (TiO2) powders synthesized for cold
spray,” Surf. Coatings Technol., 206, pp. 366-371,
2011.
[2] M. Gardon and J.M. Guilemany, “Milestones in
functional titanium dioxide Thermal Spray
coatings: A review,” J. Therm. Spray Technol., vol.
23, pp. 577-595, 2014.
[3] H. Park, J. Kwon, I. Lee and C. Lee, “Shock-
induced plasticity and fragmentation phenomena
during alumina deposition in the vacuum kinetic
spraying process,” Scr. Mater., vol. 100, pp. 44-47,
2015.
[4] L. Pawlowski, “Finely grained nanometric and
submicrometric coatings by thermal spraying: A
review,” Surf. Coatings Technol., vol. 202, pp.
4318-4328, 2008.
10 20 30 40 50 60 70 80
Inte
nsi
ty (
a.u
.)
2 theta (degree)
(101)
(004) (200) (105)(204)
Anatase TiO2
(c)
(b)
(a)
(d)
Proceedings of Mechanical Engineering Research Day 2017, pp. 410-412, May 2017
__________
© Centre for Advanced Research on Energy
Epoxy/carbon black/graphite composite bipolar plate prepared by high speed mixing technique
Y. Sudiana1, M.Z. Selamat1,2,*, S.N. Sahadan1,2, S.D. Malingam1,2, N. Mohamad3
1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 3) Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka,
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Carbon black, graphite composite, epoxy, bipolar plate
ABSTRACT – Conducting polymer composite (CPC)
has produced used epoxy resin (EP), carbon black (CB)
and graphite (G) as main composition. Various weight
percentage (wt.%) of CB, G and EP has been selected.
The fillers (CB and G) were mixed together with the
matrix (EP) used high speed mixer with no heat
treatment. The mixture was poured into the steel mold
and formed used hot pressed. After that, all sample’s
electrical conductivity and flexural strength had been
measured and the properties of EP/CB/G composite was
analyzed. The result found that the best plate produced
was the 20/25/55 of EP/CB/G weight ratio (wt.%). It has
102 S/cm in-plane electrical conductivity and 12 MPa
flexural strength.
1. INTRODUCTION
The biggest obstacle in the commercialization of
fuel cell vehicle (FCV) is the economic cost and
durability. The current situation of fuel cell system cost
for vehicle application, according to US Department of
Energy (DOE), is still more than twice as expensive as
other conventional and advanced vehicle technologies
[1]. The important component of fuel cell system is the
fuel cell stack. The stack is mainly constituting of bipolar
plate which contribute 80% of the stack weight and
almost 50% of stack cost [2]. Hence, the investigation on
cost/performance materials of bipolar plate has become a
critical research. The graphite-based composites offer
good electrical conductivity and economical processing
[3]. Addition of filler such as carbon black or carbon
nanotube to the graphite matrix has resulted in a bipolar
plate that has electrical conductivity above expected
value, but still its mechanical strength is still below
expectation [4-7]. The aim of this study is to apply the
high speed mixing technique in the fabrication of
graphite-based bipolar plate to meet DOE expectation as
shown in Table 1 below.
Table 1 DOE technical targets for bipolar plate [1]. Property 2015 Status 2025 Targets
Electrical
conductivity
> 100 [Scm-1] > 100 [Scm-1]
Flexural strength > 34 [MPa] > 25 [MPa]
2. MATERIALS AND METHODS
2.1 Materials
The conductive filler materials used in this study
were carbon black (CB) and graphite (G), while the
binder was epoxy (EP). The G powder was supplied by
Asbury Carbon Inc., that has density of 1.7 g/cm3, surface
area of 1.5 m2/g, particle size of 59 µm and 99% of purity.
The CB was also provided by Asbury Carbon Inc., that
has density of 0.096 g/cm3, has surface area of 254 m2/g,
average particle size of 30 nm, and 99% of purity. The
epoxy resin was 105 West System Epoxy Resin/206 Slow
Hardener wich has viscosity of 725 cps.
2.2 High speed mixing
Before the high speed mixing technique is applied,
samples were prepared by following steps. Firstly,
powder mixtures of CB and G were made by different
wt.% using a ball milling. To get a homogenous mixture,
the powder was mixed at rotating speed of 200 rpm for
one hour. Lastly, the powder mixture and epoxy were
mixed in the high speed mixer (Waring) at 1900 rpm
speed for 10 minutes. The liquid epoxy resin and curing
agent used in the mixture was 6:1 ratio, which is an
acceptable ratio recommended by the manufacturer. The
various composition of EP/CB/G shown in Table 2. The
composition mixture then poured into steel mould at
molding temperature 80 0C and 30-ton pressure for
30 minutes.
Table 2 The composition of composite EP/CB/G based
on weight %.
Filler Binder
G % CB% EP%
60 20 20
55 25 20
50 30 20
45 35 20
Sudiana et al., 2017
411
2.3. In-plane electrical conductivity
The in-plane electrical conductivity of the EP/CB/G
composite was measured by a Jandel Multi Height Four
Probe as per ASTM C611.
2.4. Flexural strength
The static Universal Testing Machine (Instron) was used
to measure the sample flexural strength according to
ASTM D70 at room temperature. The dimension of
samples was 100 mm x13 mm x 5 mm, the support span
length of each sample was fixed at 70 mm and the cross
head speed was 2 mm/min.
3. RESULTS AND DISCUSSION
All of the various composition of EP/CB/G was
successfully fabricated except that the 20/35/45
composition has failed. It was due to the bonding of
graphite and carbon black with EP is weak. Graphite has
poor wettability with the binder resin, while carbon black
has very large specific surface area [8-10]. Therefore,
lack of bonding to the conductive fillers during the
fabrication process of 20/35/45 composition produce the
defect of composite structure.
3.1 In-plane electrical conductivity
Figure 1 shows the effect of addition carbon black
(CB) as the second fillers in the G/epoxy composite. The
in-plane electrical conductivity of the EP/CB/G
composites has double from 20 wt.% to 25 wt.% of CB
content. The highest value of in-plane electrical
conductivity belongs to 20/25/55 composition of
EP/CB/G and the 102 S/cm of value has met the DOE
target. This phenomenon may be attributed to the better
dispersion of carbon black into the G/epoxy composite
during high speed mixing. Carbon black help build better
conductive pathway throughout the plate. Nevertheless,
addition of more than 25 wt.% of CB decreased the in-
plane conductivity because the epoxy resin as a matrix is
not sufficient enough to bind the fillers. Similar trend of
in-plane electrical conductivity also found in other study,
such as Dweiri and Sahari [4], Suherman et.al [6], and
Mathur et.al [8].
Figure 1 Electrical conductivity (Average).
3.2 Flexural strength
Figure 2 shows the trends of flexural strength from
the addition of CB to the G/epoxy composite. Similar to
the in-plan electrical conductivity above, the highest
value of flexural strength belongs to the 20/25/55
composition of EP/CB/G with the value of 12 MPa.
However, the value does not meet the DOE target. These
phenomena also present in other study that use epoxy as
binder such as Suherman et.al [6].
Figure 2 Flexural strengthy (Average).
4. CONCLUSION
The application of the high speed mixing technique
in fabrication of graphite-based bipolar plate has resulted
in a similar in-plane electrical conductivity’s and flexural
strength’s trend with other previous study but simpler in
the procedure.
ACKNOWLEDGEMENT
The authors would like to thank the Malaysia
Ministry of Higher Education, Malaysia and Ministry of
Science, Technology and Innovation for sponsoring this
work under Grant PJP/2013/FKM(6A)/S01181 and
Universiti Teknikal Malaysia Melaka (UTeM) for
financial sponsoring during this research.
REFERENCES
[1] US Department of Energy,
https://energy.gov/eere/fuelcells - accessed 12
December 2016.
[2] I. Bar-On, R. Kirchain and R. Richard, “Technical
cost analysis for PEM fuel cells,” Journal of Power
Sources, vol. 109, pp. 71-75, 2002.
[3] A. Hermann, T. Chaudhuri and P. Spagnol, “Bipolar
plates for PEM fuel cells: A review,” International
Journal of Hydrogen Energy, vol. 30, pp. 1297-
1302, 2005.
[4] R. Dweiri and J. Sahari, “Electrical properties of
carbon-based polypropylene composites for bipolar
plates in polymer electrolyte membrane fuel cell
20
40
60
80
100
120
Elec
tric
al C
on
du
ctiv
ity
(S/c
m)
20/20/60 20/25/55 20/30/50
EP/CB/G Composition
55
102
37
2
4
10
6
14
8
Flex
ural
Str
engt
h (M
pa)
20/20/60 20/25/55 20/30/50
EP/CB/G Composition
12
6
12
5
Sudiana et al., 2017
412
(PEMFC)”, Journal of Power Source, vol. 171, pp.
424-432, 2007.
[5] R. Taherian, M.J. Hadianfard and A.N. Golikand,
“Manufacture of a polymer-based carbon
nanocomposite as bipolar plate of proton exchange
membrane fuel cells,” Materials & Design, vol. 49,
pp. 242-251, 2013.
[6] H. Suherman, J. Sahari, A.B Sulong, S. Astuti, and
E. Septe, “Properties of epoxy/carbon
black/graphite composites bipolar plate in polymer
electrolyte membrane fuel cell,” Advanced Material
Research, vol. 911, pp. 8-12, 2014.
[7] M.Z. Selamat, M.S. Ahmad, M.A.M. Daud and N.
Ahmad. “Effect of carbon nanotube on properties of
graphite/carbon black/polypropylene
nanocomposites,” Advanced Material Research,
vol. 795, pp. 29-34, 2013.
[8] R.B. Mathur, S.R. Dhakate, D.K. Gupta, T.L.
Dhami and R.K. Aggarwal, “Effect of different
carbon fillers on the properties of graphite
composite bipolar plate”, Journal of Material
Processing Technology, vol. 203, pp. 184-192,
2008.
[9] R.A. Atunes, M.C.L. Oliveira, G. Ett and V. Ett,
“Carbon materials in composite bipolar plates for
polymer electrolyte membrane fuel cells: A review
of the main challenges to improve electrical
performance”, Journal of Power Sources, vol. 196,
pp. 2945-2961, 2011.
[10] M.Z. Selamat, J. Sahari, N. Muhamad and A.
Muchtar, “The effects of thickness reduction and
particle sizes on the properties graphite
polypropylene composite”, International Journal of
Mechanical and Materials Engineering, vol. 6, pp.
194-200, 2011.
Proceedings of Mechanical Engineering Research Day 2017, pp. 413-414, May 2017
__________
© Centre for Advanced Research on Energy
Low cycle fatigue of hybrid woven kenaf fiber reinforced epoxy composite with 1% addition of silica aerogel
Ellyna Chok Yee Ling, Dayang Laila Abang Abdul Majid*
Department of Aerospace Engineering, Faculty of Engineering, Universiti Putra Malaysia,
43400 Serdang, Selangor Darul Ehsan, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Natural fibers; biocomposite; fatigue
ABSTRACT - This paper presented the mechanical
and fatigue behavior of woven kenaf fiber reinforced
epoxy composites with the composition of 16.67%
kenaf and 83.33% of epoxy (1:5 weight ratio) with 1%
of silica aerogel. Hand lay-up technique was used to
prepare the specimens. Fatigue test was conducted at
constant stress amplitude, 5 Hz frequency, 0.5 stress
ratios and the maximum stress applied was from 90 %
to 70 % of ultimate tensile strength (UTS) with
decrement of 5%. From the results, tensile properties
and fatigue life improved as silica aerogel is added into
the composite.
1. INTRODUCTION
Biocomposites had been put under the spotlight
for their mechanical properties competitiveness. Kenaf
fiber had been the subject to be implemented into
biocomposite nowadays for their economic and
ecological advantages. Hence, a series of studies were
conducted in order to better understand their properties
[1-3]. Although the potential of the material is
promising, it may not be able to escape the load
demand issue which includes fatigue load. Studies
involving fatigue damage had been widely explored in
these years [4-5]. However, unlike the research works
on synthetic fibers, the works in natural fibers
especially kenaf is very lacking. Other natural fibers
besides kenaf fiber had been tested for fatigue test [6-
7]. Kenaf fibers are not the best choice to be used to
bear loads as they possess lower mechanical properties
than synthetic fibers [8-9]. Hence, silica aerogel had
been chosen as filler for the composite. This study is
then intended to explore and compare the fatigue life of
a single layer woven kenaf fiber reinforced epoxy
composite with and without aerogel in 5 different
levels of stresses.
2. METHODOLOGY
Tensile test was used to investigate the properties
for the specimens before performing fatigue test. The
test is performed using the 10 kN Servo Hydraulic
Instron Machine (Instron 3366). The test was
conducted by setting a standard strain rate of
0.01𝑚𝑖𝑛−1 and head displacement rate of 2𝑚𝑚/𝑚𝑖𝑛
according to ASTM D3039. ASTM D3479 on the other
hand is used to conduct the fatigue test on the
specimens through the tension-tension fatigue loading
mode. Stress ratio used is 0.5 with frequency of 5 Hz.
The stress levels are varied from 90%, 85%, 80%, 75%
and 70% of the ultimate tensile strength (UTS). The
specimens were cycled using 810 Material Test System
(MTS) machine with the number of cycles to failure
recorded by data acquisition system.
3. RESULTS AND DISCUSSION
3.1 Tensile results
Figure 1, and 2 below exhibit the load-
displacement and stress-strain curves of all categories
of specimens. It is shown that kenaf composite that is
added with 1% of silica aerogel is 27.3% higher in
UTS compared to kenaf/epoxy composite that is
without addition of silica aerogel. However, the
Young’s modulus decreases with the addition of silica
aerogel.
Figure 1 Load displacement curves for all three
materials.
Natural fibers are reported to possess high
strength. However, following the experiment
conducted, the tensile properties of both kenaf/epoxy
and Kenaf/Epoxy/Silica Aerogel composites are lower
than pure epoxy. The incompatibility of fibers and
matrix is the main cause in this behavior. The
incompatibility hence brings inefficiency of stress
transfer in the matrix.
3.2 Fatigue results
Fatigue test was conducted using different stress
levels. The average number of cycles to failure for all
three categories is tabulated in Table 1.
From Figure 3, it can be observed that the fatigue
life of pure epoxy is higher than kenaf/epoxy/silica and
kenaf/epoxy. Kenaf/epoxy composites have the lowest
fatigue life compared to all three specimens. However,
the addition of silica aerogel into the kenaf/epoxy
Ling et al., 2017
414
composites has boosted the properties of the
composites by more than 100% in every stress level. It
can hence be concluded that the fatigue life increases
significantly with the addition of 1% of silica aerogel.
Table 1 Average fatigue life data for the specimens.
Stress
Level
(UTS)
Number of cycles to failure
Pure
Epoxy
Kenaf/epoxy/silica
aerogel Kenaf/epoxy
0.90 1821.3 316.0 7.3
0.85 4593.3 751.3 112.3
0.80 5646.7 4186.0 208.7
0.75 10070.0 5632.7 1085.7
0.70 13620.3 12449.2 5177.3
(a)
(b)
Figure 2 (a) UTS and (b) Young's Modulus for all three
materials.
Figure 3 S-N curve generated for all tested specimens.
The pure epoxy exhibits better fatigue behavior
compared to the kenaf composites. The incompatibility
of fibers and matrix is the main cause in this behavior.
The incompatibility hence brings inefficiency of stress
transfer in the matrix [10].
4. CONCLUSION
The study verified that the addition of silica
aerogel into composites provide better tensile and
fatigue properties. In terms of tensile test, the ultimate
tensile strength increases with the addition of silica
aerogel but the Young’s modulus is decreased. Hence,
it can be said that there is a trade off in implementing
the composite into any sorts of structures. On the other
hand, the composite provides significant increment in
fatigue strength than composites without addition of
silica aerogel. The composite can then be candidates
for applications that are tend to be subjected to fatigue
phenomenon.
REFERENCES
[1] A. Bakar, S. Ahmad and W. Kuntjoro, “The
mechanical properties of treated and untreated
kenaf fibre reinforced epoxy composite,” Journal
of Biobased Materials and Bioenergy, vol. 4, no.
2, pp. 159-163, 2010.
[2] T. Hojo, Z. Xu, Y. Yang and H. Hamada, “Tensile
properties of bamboo, jute and kenaf mat-
reinforced composite,” Energy Procedia, vol. 56,
pp. 72-79, 2014.
[3] N.A.K. Hafizah, M.W. Hussin, M.Y. Jamaludin,
M.A.R. Bhutta, M. Ismail and M. Azman,
“Tensile behaviour of kenaf fiber reinforced
polymer composites,” Jurnal Teknologi, vol. 3, pp.
11-15, 2014.
[4] K.L. Reifsnider and A. Talug, “Analysis of fatigue
damage in composite laminates,” International
Journal of Fatigue, vol. 2, no. 1, 3-11, 1980.
[5] J.W. Holmes, B.F. Sørensen, Fatigue behavior of
continuous fiber-reinforced ceramic matrix
composites, Butterworth-Heinemann; 1995.
[6] S. Liang, P.B. Gning and L. Guillaumat, “A
comparative study of fatigue behaviour of
flax/epoxy and glass/epoxy composites,”
Composites Science and Technology, vol. 72, no.
5, pp. 535-543, 2012.
[7] F. de Andrade Silva, N. Chawla and R.D. de
Toledo Filho, “An experimental investigation of
the fatigue behavior of sisal fibers,” Materials
Science and Engineering: A, vol. 516, no. 1, 90-
95, 2009.
[8] H. Akil, M.F. Omar, A.A.M. Mazuki, S.Z.A.M.
Safiee, Z.M. Ishak and A.A. Bakar, “Kenaf fiber
reinforced composites: A review,” Materials &
Design, vol. 32, no. 8, pp. 4107-4121, 2011.
[9] B.M. Philip, E. Abraham, B. Deepa, L.A. Pothan
and S. Thomas “Plant fiber-based composites,”
Green Composites from Natural Resources, CRC
Press, pp. 95-124, 2014
[10] H.D. Rozman, G.S. Tay, R.N. Kumar, A.
Abusamah, H. Ismail and Z.M. Ishak,
“Polypropylene–oil palm empty fruit bunch–glass
fibre hybrid composites: a preliminary study on
the flexural and tensile properties,” European
Polymer Journal, vol. 37, no. 6, pp. 1283-1291,
2001.
Proceedings of Mechanical Engineering Research Day 2017, pp. 415-417, May 2017
Compressive behaviour of filament wound steel/carbon hybrid composites tube
N.A. Jamaluddin1,*, S.A. Hassan1,2, B. Omar3, U.A. Hanan1, M.A.M. Adam1
1) Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Skudai Johor, Malaysia
2) Centre for Composites, Institute for Vehicle and System Engineering, Universiti Teknologi Malaysia,
81310 Skudai Johor, Malaysia
3) Department of Structure and Materials, Faculty of Civil Engineering, Universiti Teknologi Malaysia,
81310 Skudai, Johor, Malaysia
*Corresponding e-mail: [email protected]
Keywords: Composites; crashworthiness; energy absorption
ABSTRACT – The crushing behaviour of composites
tube were investigating by applied the different layer in
filament winding process which is the CCC and CSC
samples. Compression test on CCC and CSC epoxy
composites hexagonal tubes were conducted. Effect of
height of the tube and comparison between CCC and
CSC samples on the load-displacement behaviour as
well as energy absorption of composites hexagonal
tubes has been investigated. Results obtained shows
that, CCC samples stands higher load and energy
absorption capability than CSC samples. However, the
important parameter for crashworthiness is specific
energy absorption and crush force efficiency which is
for ideal crashworthiness.
1. INTRODUCTION
Composite parts as sandwich structures are
specifically used in applications for automotive,
aerospace and vehicle industries. Approaches reducing
the weights of vehicles using polymers most frequently
involve replacing ferrous and non-ferrous metals with
polymers and increasing the specific strengths and
rigidities of polymers. Researches into polymers for use
in lightweight vehicle are classified into high
performance polymers, polymers for weight reduction,
reinforced polymer composites, polymer sandwich
panels, and polymer/metal hybrid systems. Weight
reduction of vehicle is very important because vehicle
weight directly affects energy consumption [1]. An
important parameter when studying energy absorption is
the energy absorbed per unit mass of crushed material.
This is often called the specific energy absorption
(SEA). Schultz [2], has conduct research on effect of
geometry which is subject of the ability to absorb
impact energy and be survivable for the occupant is
called the ‘‘crashworthiness’’ of the structure.
Crashworthiness is concerned with the absorption of
energy through controlled failure mechanisms and
modes that enable the maintenance of a gradual decay in
the load profile during absorption. Therefore, in this
paper, inclusive experimental work was implemented to
study the response of crushing behaviour on composites
tube by applying different layer in filament winding
process with different length which are 40 mm and 45
mm. The winding angle that was chosen is 45° as in
previous studies done by Misri [3] which indicated that
the value of energy absorption for 45° winding angle is
higher compared to 90°.
2. METHODOLOGY
In this experiment, two types of composites will be
produced: Carbon-Carbon-Carbon (CCC) and Carbon-
Steel-Carbon (CSC) at 45° winding angle using filament
winding process. Then, the composites are cut into two
different heights which is 4.5 cm and 4 cm respectively
as shown in Fig. 1. The upper and lower ends of the
composites are trimmed properly and attached with
strain gauge (FCA-1-11) with a gauge length of 1 mm
and gauge resistance of 120 ± 0.5 Ω. The strain gauge
was attached at an angle of 0° and 90° and the channel
were soldered with wire and will be later attached to
data logger. Compression test provides a standard
method of obtaining data for research and development,
quality control, acceptance or rejection under
specifications and special purposes. From the test as
shows in Fig. 2, the behaviour of the core, maximum
load, compression strength, modulus, extension, strain
and energy absorption of the core had been determined.
Figure 1 Samples for (a) CCC 45mm, (b) CCC 40mm,
(c) CSC 45mm and (d) CSC 40mm.
Jamaluddin et al., 2017
416
Figure 2 Sample under compression test.
3. RESULTS AND DISCUSSION
Based on the compression that were conducted, the
result shows in form of Load-Displacement curves and
Stress-Strain curves. According to the load displacement
curves in Fig. 3 and Fig. 4, the CCC composites tube
behave linearly first and the axial load is absorbed as an
elastic strain energy in the material and same goes for
CSC tube but however the for CCC, the elastic slope is
greater compared to CSC and this can be seen from
graph for 40 cm specimen and 45 cm specimens as both
shows the same. Elasticity is the ability of an object or
material to resume its normal shape after being
compressed and modulus of elasticity is a measure of
the ability of a material to withstand changes in length.
Figure 3 Load-Displacement curve for CCC and CSC
with samples length of 40 mm.
Figure 4 Load-Displacement curve for CCC and CSC
with samples length of 45 mm.
The value of the Compressive Modulus can be
calculated from the Combined Stress-Strain curves
shown in Fig. 5 and Fig. 6 as it is equivalent to the
value of the gradient and the data calculated were
presented in Table 1.
Figure 5 Stress-Strain Graph for CCC and CSC with
samples length of 40 mm.
From the table it is clearly shows that the
Compressive Modulus for 3 layers of Carbon samples
are greater compare to CSC samples. Although it can
withstand load, but after it reaches to a peak load, the
CCC specimens fail suddenly or catastrophically and it
can be seen from the load-displacement curves for both
40 mm and 45 mm specimens as the load drops down
by compressive shear parallel to fibre.
Table 1 Value of Compression Modulus according to
samples.
Sample Compressive Modulus, MPa
CCC 40 294.77
CSC 40 184.858
CCC 45 511.61
CSC 45 254.43
It occurs when unstable interlaminar or
intralaminar crack growth occurs and also in long thin
walled tubes because of column instability [1] . As a
result of this, the actual magnitude of specific energy
absorbed is much less and the peak load is too high to
prevent injury to the passengers. The crush mode of
CCC 40 and 45 mm are shown in Fig. 7.
Figure 6 Stress-Strain Graph for CCC and CSC with
samples length of 45 mm.
Figure 7 Crush Mode (a) CCC 45 mm, (b) CSC 45 mm,
(c) CCC 40 mm and (d) CSC 40mm.
(a) (b) (c) (d)
Jamaluddin et al., 2017
417
4. CONCLUSION
Overall, the purpose of this study is to analyse the
effect of core height on the crashworthiness parameter
and to study the mechanical behaviour of filament
wound steel/carbon hybrid hexagonal tube composites
under compression load. From the analysis that have
been made to the hexagonal structure, it can be conclude
that the Carbon-Steel-Carbon have a good potential in
energy absorber.
REFERENCES
[1] A. Alias and Y.S. Ismail, “Composite materials,”
Universiti Technologi Malaysia, 2003.
[2] M.R. Schultz, “Energy absorption capacity of
graphite-epoxy composite tubes”, Master of
Science Thesis, Virginia, pp. 110-115, 1998.
[3] S. Misri, M.R. Ishak, S.M. Sapuan and Z. Leman,
“The effect of winding angles on crushing
behavior of filament wound hollow kenaf yarn
fiber reinforced unsaturated polymer composites,”
Fibers and Polymers, vol. 16, no. 10, pp. 2266-
2275, 2015.
Proceedings of Mechanical Engineering Research Day 2017, pp. 418-419, May 2017
__________
© Centre for Advanced Research on Energy
Synthesis of oxygen carrier for chemical looping combustion from iron ore N.F. Afandi1,*, Wen Liu2, A. Manap1, D. Naidu1
1) Faculty of Mechanical Engineering, Universiti Tenaga Nasional, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor
2) Cambridge Centre for Advanced Research in Energy Efficiency in Singapore,
Nanyang Technological University, 637459, Singapore
*Corresponding e-mail: [email protected]
Keywords: CLC; Fe-based; iron ore
ABSTRACT – Chemical looping combustion (CLC) is
a promising technology for fossil fuel combustion that
prevents greenhouse gas (GHGs) release into the
atmosphere. In CLC, oxygen carrier provides oxygen
during combustion process. This research focuses on
using iron ore that was found at iron mining site, Kuantan
Pahang as oxygen carrier. Iron ore was grinded to sub-
micron sized particles to increase performance of CLC.
Then, the phase and morphology of the powder was
characterized to evaluate the Fe2O3 content. Fe2O3 shows
favorable thermodynamics in CLC application. This
research succeeded in producing sub-micron sized iron
ore particles that contain high Fe2O3, which is suitable to
be used as oxygen carriers in CLC application.
1. INTRODUCTION
Chemical looping combustion (CLC) is a carbon-
capturing technology that uses oxygen carriers (OCs) to
provide oxygen during combustion process. Hence, it
reduces the emission of greenhouse gases (GHGs) into
the atmosphere. OCs play an important role in CLC
performance [1]. Suitable oxygen carriers should have
good fluidization properties, high oxygen content and the
capacity to convert fuel to CO2 and H2O, low cost and
environmental friendly [2].
There are 5 metal based OCs that are usually used
in CLC, which include Fe-based, Ni-based, Co-based,
Mn- based and Cu-based [3]. From previous studies, Cu-
based and Ni-based shows good performance as oxygen
carriers. However, Cu-based cannot withstand at high
temperature because it has low melting point temperature
and Ni-based is costly and needed special safety measure
to handle this material due to its hazardousness [4-5].
Mn-based has low reactivity with fuels that can reduce
efficiency of CLC system. Meanwhile the Co-based is
highly cost and toxic to the nature [6]. This research
focuses on Fe-based oxygen carrier since it is more
environmental friendly than other OCs, abundant, and
low cost, thus substantially reducing the operational cost
[4]. In recent years, iron ores have become popular source
for Fe-based OCs due to its high reactivity in CLC,
especially iron ores that contain high amounts of Fe2O3
[7].
This research aims to investigate the suitability of
mineral iron ore found at iron mining site in Kuantan,
Pahang as OCs to be used in CLC. The iron ore was
characterized using X-Ray Diffraction (XRD), Field
emission Microscopy (FESEM) and Energy Dispersive
X-Ray (EDX) to determine the crystalline phase,
morphology and elements of the obtained iron ore.
2. METHDOLOGY
The iron ore samples were collected from iron
mining site at Kuantan, Pahang. The weight of the iron
ore was 200g. Then, iron ore was crushed using mortar
for 15 to 20 minutes. High blender DM-6 was used to
grind the iron ore (raw material). The iron ore was
grinded at 20 000 rpm for 30 minutes into micron size
particles using tungsten carbide blade.
The sub-micron sized iron ore materials were then
characterized. Phase was identified using XRD
(SHIMADZU 6000) that uses CuKα radiation at a scan
speed of 3°/min. The data were collected at scan range of
20° to 80° with voltage and current of 30 kV and 20 mA
respectively. Meanwhile, morphology was observed
using FESEM (HITACHI SU8030) with acceleration
voltage from 1 to 5 kV. The elemental composition of the
powder was analyzed using EDX.
3. RESULTS AND DISCUSSION
Figure 1 shows XRD result of iron ore after
grinding for 30 minutes. Presence of Fe2O3 can be
observed in Figure 1 corresponding to Fe2O3 structure
(JCPDS card no: 39-1346 and 25-1402). The conversion
of Fe2O3 to Fe3O4 shows favorable thermodynamics in
CLC. Hence, high composition of Fe2O3 is needed in OCs
to increase the performance and efficiency of CLC [4].
Figure 2(a) shows the microstructure of raw iron
ore. They are irregularly shaped with particle size of
more than 300 nm. Figure 2(b) shows microstructure of
iron ore after grinding. Particle size ranging between
150nm-900nm can be achieved using grinding process.
Based on Song et al. [7], OCs with smaller particles are
more stable at high temperature, have superior
mechanical properties and are capable of reducing the
sulphur content that comes from the solid fuel, which is
not favorable in CLC. The sulphur presence can be
deteriorating the oxygen carrier hence decrease the
function of redox reaction. Therefore, it can decrease the
efficiency of CLC [8].
Afandi et al., 2017
419
Figure 1 XRD result of iron ore after had been grinded
about 30 minutes.
Figure 2 Microstructure result of iron ore (a) raw
material (b) after grinding process.
Figure 3(a) shows EDX analysis of raw iron
ores and Figure 3(b) shows iron ores after grinding. EDX
analysis shows no impurities for both samples. The
sample was not contaminated even after the grinding
process. Therefore, this iron ore is fit to be tested in
thermogravimetric analysis (TGA) in order to simulate
its performance in CLC application.
Figure 3 Elemental compositions of iron ore (a) raw
material (b) after grinding process.
4. CONCLUSIONS
Iron ore that was collected from iron mining site at
Kuantan, Pahang can be used as OCs since it contains
high Fe2O3 that can increase performance of CLC.
Moreover, this iron ore is the least expensive metal that
is accessible in nature and give less impact to the
environment. This powder will be tested using TGA for
its performance as oxygen carrier.
ACKNOWLEDGMENT
The authors acknowledge the financial supports by
the Malaysian Ministry of Higher Education (Grant No.
FRGS20160105).
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