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Modernization of two cycles (MA, BA) of competence-based curricula in
Material Engineering according to the best experience of Bologna Process
Composite materials:
challenges for the future
Jan Ivens
Lecture at the Sami Shamoon College of Engineering
2
Content
• Introduction
• Example of a smart material: shape memory foam
• Composite Materials
• Challenges for composite materials
• Answers through composites manufacturing
3
New materials?
At the start of the construction of the
Sagrada Familia (1882):
a few hundred materials:
Virtually no plastics
Now > 45000
No light-weight metal alloys
Now a few thousand
No composites
Now a few hundreds
Today: more than 160.000 materials
Antoni Gaudi
4
Scientific American:
9 Materials That Will Change the
Future of Manufacturing
Anisotropic plastics
Ultrathin platinum
coatings
Cheaper carbon fibre
5
Mega-magnets
Nano-crystals
Hard coatings
Thermo-electrics
Electric ink Intelligent foam
6
Filling the gaps in the Ashby maps
HOLE E/ρ
Contours of
E/ρ
Vector for
material development
7
Anisotropic and hybrid materials
Smart materials
GOAL: Energy efficiency –
material efficiency
10
Shape memory alloys
11
Shape memory polymers
Source: http://www.ctd-materials.com/products/emc.htm
12
Characteristics of the materials
response
TMA resultspeak stress relaxation stress spring back recovery stress
MPa MPa % MPa10% 65° 3.65 ± 0.45 1.95 ± 0.15 0,45 ± 0,35 1.65 ± 0.3
75° 2.4 ± 0.2 1.75 ± 0.12 0,25 ± 0,10 1.60 ± 0.0685° 2.2 ± 0.2 1.75 ± 0.15 0,15 ± 0,05 1.65 ± 0.12
20% 75° 5.9 ± 1.3 3.9 ± 0.5 2 ± 1 3 ± 1
-1
0
1
2
3
4
Str
ess
(M
Pa)
0 10 20 30 40 50 60
Time (min)
Recovery 65°C– – – – Deformation 65°C––––––– Recovery 75°C– – – – Deformation 75°C––––––– Recovery 85°C– – – – Deformation 85°C–––––––
Universal V4.5A TA Instruments
65°C 75°C 85°C
Deformation
Recovery
13
Shape memory foam
• Light-weight part
• stability by dimension
• Minimize transport volume
• Versatile shape
• Customizing
14
Minimal transport volume
15
Ultra compressible
Controlled compaction
16
20
MIN
Regaining shape
17
diatom structuresHighly patterned with a variety of patterns, ribs,minute spines, marginal ridges and elevations
Internal heating by radiation
18
Prototype mould concept
1st injection
(interior)
Placing of heating
bundle
2nd injection
(exterior)
final
shape(heating
bundle
embedded)
heat and
compress
19
Design challenges
1. Functional use: dimensional stability
o Optimisation of the geometry
2. Creating the temporary shape
o Analysis of the deformation of the foam
o Design of the compaction process
3. Returning to the permanent shape
o Stimulus requirement
o Completeness of recovery
o Repeatability
4. Triggering the transformation
o Selection of heating elements
o Optimisation of distribution and heating control
5. Surface finish
o Scratch and wear resistant
o “look”
Modernization of two cycles (MA, BA) of competence-based curricula in
Material Engineering according to the best experience of Bologna Process
Composite materials
21
What is a composite material?
An artificial attempt to mimick the complexity of nature
Ex. bamboo
Hemicellulose
Lignin
22
Hierarchy in composites
3 meter
50 mm
5 mm
0.05 mm
0.005 mm
23
The constituents
• Fibres!
o Are very thin (0.01mm) hence very flexible (even if the material is intrinsically stiff)
o Can be woven, braided, knitted... and remain flexible, easy to handle
• The polymer matrix
o Is light, colourful or transparent, easy to shape,
o Can be liquid like water and hence easy to impregnate the fibrousreinforcements
24
Elementary steps for the manufacturing of a composite part
Impregnation
Resin/matrix
COMPOSITE
Consolidation
Knitting
WeavingBraiding etc
Fibres
25
Thermosets (epoxy, polyester)
Fibers Force Composite
Curing time
matrix
Resin Hardener
Thermoset
26
Thermoplastics (polypropylene, nylon,
PVC, PC)Fibers Heat
Force
Composite
Thermoplastic
matrix
27
Prime application field: moving
objects
Carbon laminate
Carbon sandwich
Fiberglass
Aluminum
Aluminum/steel/titanium pylons
Composites
50%
Aluminum
20%
Titanium
15%
Steel
10%
Other
5%
28
The first composites in furniture design
• Charles Eames (1907-1978) !• Engineer in a Steel Mill … architect … designer … artist…
• … living in Los Angeles in the late ’40s• centre of modern airplane industry• glass fibres and polyesters invented
mid-30’s• first used in (military) airplanes during
WWII
29
Charles Eames’ discovery of
materials - 2• “plastic” chairs offered the solution: glass fibre reinforced polyester (both
materials developed only 10 years earlier!!)
30
The 60’s: technical experiments...
Verner Panton
1968
(glass fibre-polyester,
later glass fibre-polyurethane)Eero Arnio
1971
(glass fibre-polyester)
31
The introduction of carbon fibres...
Pol Quadens
1993
(carbon fibre-epoxy)
The lightest chair in the world!
(< 1 kg)Alberto Meda
1987
(carbon fibre-epoxy)
32
Thermoplastic composites ...
• Glass fibre-polypropylene, a thermoplast!
• Production method: injection moulding of short-fibre reinforced PP!
Jasper Morrison, 1999
(glassfibre-polypropylene) Stefano Giovannoni, 1999
(glass fibre-polypropylene)
33
Composites inspire designers
• Freedomo to experiment in small series
o of shapes, colours, textures in the material
• It’s hi-techo light, stiff ànd strong!
o Beware of fibre orientation and volume fraction
• On the wave of sustainabilityo Lighter products less energy consumption
34
Freedom of design and shaping
“Floris”, 1967, Günther Beltzig
(Glass-polyester)“Jet Desk”, 2008, Brodie Neill
(carbon-epoxy)
35
Freedom of design and shaping
Zaha Hadid
Yacht Blohm & Voss
36
Composites inspire designers
• Freedomo to experiment in small series
o of shapes, colours, textures in the material
• It’s hi-techo a real need: light, stiff ànd strong!
o Beware of fibre orientation and volume fraction
• On the wave of sustainabilityo Lighter products less energy consumption
37
Comparing strength su vs. stiffness E
glas-UD
CFRP-0/90
PA
Ti
CFRP-UD
Cr-Mo-staal
C-staalAlPA-glas
hout
glas-PEs-mat
0
200
400
600
800
1000
1200
1400
1600
0 50 100 150 200 250
STIJFHEID (GPa)
ST
ER
KT
E o
f V
LO
EIG
RE
NS
(M
Pa)
Carbon fibre
glass fibre
ST
RE
NG
TH
or
YIE
LD
ST
RE
SS
(M
Pa)
STIFFNESS
38
Criteria for minimising the mass of a
square rod / flat plate (thickness free)
Bending of a flat plate:
Bending of a square
rod:
tension/compression
of a rod or plate
strengthstiffnessM = mass
EM
~
u
Ms
~
EM
~
3 2~
u
Ms
3~
EM
u
Ms
~
39
CFRP-UD
hout
CFRP-0/90
glas-PEs-UD
Alglas-PEs-mat
TiPA-glasPA
Cr-Mo-staalC-staal
0
10
20
30
40
50
60
70
80
90
0 1 2 3 4 5 6 7 8
SPECIFIEKE STIJFHEID (buiging)
SP
EC
IFIE
KE
ST
ER
KT
E (
bu
igin
g)
Specific bending strength (su)1/2/
and bending stiffness (E)1/2/
42
Unidirectional carbon fibre composites
60%
50%
60%
50%
30%
40%
Polyme
r 0%
Carbon
fibre 100%
Polymer 0%
60%Ec,l = Vf*Ef + Vm*Em
Ec,t = (Vf/Ef + Vm/Em) -1
43
Carbon reinforced composite (50% fibres):
weaves, random mats, short fibre composites
60%
50%
Polymer
0%
Carbon
fibre 100%
40%
50%50%
30%
44
60%
50%
60%
50%
40%
Polyme
r 0%
Carbon
fibre 100%
Each fibre architecture gives different composite properties…
randomly
oriented long
fibre
composites
unidirectional
composites
Woven or
cross-ply
composites
Injection molded short
fibre composites
45
Composites inspire designers
• Freedomo to experiment in small series
o of shapes, colours, textures in the material
• It’s hi-techo a real need: light, stiff ànd strong!
o Beware of fibre orientation and volume fraction
• On the wave of sustainabilityo Lighter products less energy consumption
46
Lightness is important for transport ...
47
Lighter cars lower fuel
consumption !
48
Boeing 787 Dreamliner: 50%
composites
49
Then … why don’t we use
composites all over (yet)?Composites face some challenges
o Freedom in shape
• Yes, If you have
• Enough time to make the part
• Enough money to pay for it
o High performance
• Yes, but
• Not in all directions
• Not all properties are high
o Light and thus environment friendly
• Yes, but
• High energy needed to produce the part
• Low level of recycling
50
Properties drop tremendously due to
fibre misorientationo For carbon-epoxy
Properties of laminated structures 50
q
51
Fibre length has a significant effect on
composite performance
Source: Spörrer, Sandler, Altstädt, UniBayreuth
52
Autoclave curing
l Pressure limited to 15 bar
l Large pressure chamber (autoclave)
l Complete temperature cycle (up to 15 hours!)
l High performance composite parts
l Aerospace
l Sports
l Base material “prepreg”
53April 2007-ivj
54
Resin Transfer Molding
• Schematic process description
o Fibrous reinforcement (precut or preformed) is placed in an open mold
o The mold is closed, the reinforcement is compacted
o Resin is injected at low pressure in the closed mold
o After complete filling, the resin is allowed to cure
o After cure, the part is demolded
55
Injection molding
• Pellets with short fibres
o Length 0.1 to 3 mm
• Very high pressure
o Up to 4000 bar
o Constraints on part size
• Short cycle times
o < 1 minute
• Low production waste
• Limited finishing times
• Properties
o Improved strength – stiffness
• Limited due to fibre length
o Improved thermal stability
o Reduced toughness
56
Enough time to make a part?
RTM
Series size
Perf
orm
an
ce
autoclave
Filament
winding
pultrusion
Hand lay-up
Spray-up
RIMInjection molding
thermoforming
Compression
molding
The holy grail of
composites manufacturing
Discontinuous fibres
Continuous
fibres
Modernization of two cycles (MA, BA) of competence-based curricula in
Material Engineering according to the best experience of Bologna Process
New technologies
LFT injection molding
LFT compression molding
Thermoforming with continuous fibre
High Pressure RTM
Combined technologies
58
Longer fibers in IM
• Injection molding:
o Short fibers in pellets
o Severe fiber shortening in extruder
• solution: long fiber thermoplastic (LFT)
59march 2009 Composites production technology 59
Effect of fiber length
60
Effect of fiber length
Modernization of two cycles (MA, BA) of competence-based curricula in
Material Engineering according to the best experience of Bologna Process
New technologies
LFT injection molding
LFT compression molding
Thermoforming with continuous fibre
High Pressure RTM
Combined technologies
62
Thermoforming with continuous
fibers• Goal: increase in mechanical properties
• Problems:
o Preimpregnated plates
o Reduction of formability
o Complex deformation mechanisms
Continuous Production on a
Double band press
Unwinding Stations
for Fabric and Polymer
Films
Press Corpus
pressure and
temperature is applied
Impregnation,
consolidation and
solidification of the
material
Cutting station Palletizing
64
Deformation mechanisms
Thermoforming
Separate heating and forming
Forming pressure from 5 bar, since laminates are already fully consolidated
Cycle times typically within a minute
Reproducible process
1. Heating 2. Position of the
heated sheet
3. Forming
and cooling
4. Ejecting
of the part
5. Post
processing
Modernization of two cycles (MA, BA) of competence-based curricula in
Material Engineering according to the best experience of Bologna Process
New technologies
LFT injection molding
LFT compression molding
Thermoforming with continuous fibre
High Pressure RTM
Combined technologies
67
Resin Transfer Molding
68
High pressure RTM
69
High Pressure RTM on snap-cure PU
start
injection
central
pressure
sensor
pressure sensors
at the side
stop
injection
increase press power
from 200 t to 300 t
Injection time: 46 s
70
Reducing cost: better performance in less
time
Formulation “C”Formulation “C”
Formulation “C”
D
Ta
rge
t Z
on
eFormulation “C”
D
No
break
D D
Tensile
DInitial !
Results from EU-project HIVOCOMP (material: Huntsman)
71
72
73
Automation for improved productivity costs
BMW i3
Modernization of two cycles (MA, BA) of competence-based curricula in
Material Engineering according to the best experience of Bologna Process
New technologies
LFT injection molding
LFT compression molding
Thermoforming with continuous fibre
High Pressure RTM
Combined technologies
75
Hybrid processes
• Problem statement
produce high performance complex parts in short cycle
times
• solution: hybrid processes
o Thermoplastics: short cycle
o Continuous fibers for high performance: thermoforming
o Disadvantage thermoforming:
• Limited complexity
• No integration of inserts, ribs possible
o Complex shapes: injection molding or compression
molding
76
Continuous fiber: FRTP sheet
• Sheet thickness: 0,05 mm – 6,0 mm
• Sheet width: 620 mm or 860 mm
• Fibers: glass, carbon, aramid
• Matrix: PP, PA6, PA12, PA66, PPS, TPU
• Fiber volume content: 35% - 60%
• Structure: unidirectional and
balanced
77
Separate heating and forming
Forming pressure from 5 bar, since laminates are already fully consolidated
Cycle times typically within a minute
Reproducible process
1. Heating 2. Position of the
heated sheet
3. Forming
and cooling
4. Ejecting
of the part
5. Post
processing
Thermoforming
78
Injection moulding of hybrid
structuresLFT moulding of hybrid
structures
Hybrid processing methods
79
Outer shell with
TEPEX®
Injected, short or long fiber
polymers to strengthen the part
and for function integration
Hybrid Forming
80
81
Examples (Audi)
82
Hybride
technieken
RTM .
Thermo-
vormen
conclusion
Seriegrootte
Perf
orm
an
tie
autoclaaf
wikkelen pultrusie
Handlamineren
Spray-up
RIMspuitgieten
thermovormen
warmpersenLFT-IM
LFT-persen
HP RTM
83
Modernization of two cycles (MA, BA) of competence-based curricula in
Material Engineering according to the best experience of Bologna Process
Extra slides
Then … why don’t we (yet)?
Composites face some challenges
o Freedom in shape
• Yes, If you have
• Enough time to make the part
• Enough money to pay for it
o High performance
• Yes, but
• Not in all directions
• Not all properties are high
o Light and thus environment friendly
• Yes, but
• High energy needed to produce the part
• Low level of recycling
Different fibre architectures, different composite properties…
60%
50%
60%
50%
40%
Polymer
0%
Carbon
fibre 100%
unidirectional
composites
cross-ply
composites
randomly
oriented
composites
Consequence: damage
• Delaminations
• Matrix cracks
How to minimize damage?
How to predict the effect of
damage on composite
properties
Improving toughness by controlled damage
Goal: to improve composite strain to failure without sacrifice of the stiffness
Long term interest: impact resistance, damage tolerance
Novel hybrids (brittle fibers in combination with ductile fibers)
s
s
How to introduce ductility in
the brittle composite?
Through control of the process
of damage development
PseudoductileBrittle
(a) (b) (c) (d) (e)
Delamination#1
Delamination#2
Delamination#4
Nanoscale toughening
no CNTs Curved CNTs Aligned CNTs
Effective μ-scale stress suppression‼ CNT orientation and waviness!
CNT localization
μ-scale stress concentrations elimination NO stress rise in rest of matrix
Smart CNT-networks: “bridges”
Location: high stress zones
Intelligent composites
AE
sensor
on-board
computer
super-
computer
structural
health analysis
decision on
maintenance
Self-reinforced composites
• Self-reinforced polypropylene
o Fibre = drawn PP
o Matrix = isotropic PP
• Hot compaction
Apply T Apply P
Apply T and P
Kmetty et al., Progress in Polymer Science (2010)
Tackling brittleness: SRPP
Ward et al, Polymer (2004)
Tackling brittleness: tough fibres
Silk composites
Excellent falling weight impact performance!
Patent: WO 2007-110758
94
Steel fibre composites
5 mm5 mm
Steel fibre
yarn
Then … why don’t we (yet)?
Composites face some challenges
o Freedom in shape
• Yes, If you have
• Enough time to make the part
• Enough money to pay for it
o High performance
• Yes, but
• Not in all directions
• Not all properties are high
o Light and thus environment friendly
• Yes, but
• High energy needed to produce the part
• Low level of recycling
Recycling options
But it’s not just recycling!
0% 20% 40% 60% 80% 100%
Passenger car
2t truck
4t truck
10t truck
Bus
Material production Parts & vehicle productionUse MaintenanceWaste Transport
Source: prof. Jun Takahashi, University of Tokyo
Energy cost in manufacturing
Carbon fibre:
Natural Fibres and Bio-polymers: why?
• Cost: often (potentially) low cost
• Less abrasive
• Good specific mechanical properties (low density)
• Natural image, design aspects, renewable and environment-friendly
• good acoustic & vibration damping, radar transparency, low CTE, ...
Specific tensile modulus E/rho (MJ/kg) for various
fibres
0
20
40
60
80
100
120
140
Flax fibre Bamboo
fibre
Glass fibre Carbon fibre
Sp
ecif
ic m
od
ulu
s (
MJ/k
g)
Specific FLEXURAL modulus (E(1/3)/rho in
N(1/3)m(7/3)/kg) for various fibres
0
0.5
1
1.5
2
2.5
3
3.5
4
Flax fibre Bamboo
fibre
Glass fibre Carbon fibreSp
ecif
ic b
en
din
g m
od
ulu
s (
N(1
/3)m
(7/3
)/kg
)
Flax composites compete with glass
for tension
for bending
Need to optimize fibre orientation!UD, no twist
Special preforms for composites
UD PREPREGS ROVINGNON-CRIMP FABRIC
Future developments
• Manufacturing time
o Robustness of manufacturing
o Cycle times < 5 minutes
o Hybrid processing
• Toughness: Hybridization by combining
o Tough fibres with stiff fibres
o Continuous fibres with oriented discontinuous fibres
• Environmental aspects
o Recovery of fibres from composite waste
• Minimizing recycling damage
• Maintaining fibre properties
o Biocomposites
• Performant biopolymers
• Improved environmental resistance (water, UV)