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http://www.iaeme.com/IJCIET/index.asp 139 [email protected]
International Journal of Civil Engineering and Technology (IJCIET)
Volume 9, Issue 10, October 2018, pp. 139–152, Article ID: IJCIET_09_10_015
Available online at http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=9&IType=10
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
©IAEME Publication Scopus Indexed
FINITE ELEMENT STUDY ON HOLLOW
CORRUGATED STEEL BEAMS UNDER IMPACT
LOADING
Mohammad R.K.M. Al-Badkubi
Building and Construction Technical Engineering Department,
College of Technical Engineering, the Islamic University, Najaf, Iraq
ABSTRACT
This paper presents a nonlinear finite element analysis on the behavior of
corrugated steel beams subjected to impact load using ABAQUS (6.14-4) computer
program. Six corrugated steel beams with length 1.8 m and three unit profile of
corrugated steel for each side of the square cross section rested on fixed steel blocks
at the ends were modeled. The parametric study was made on the corrugated steel
plate thickness and the magnitude of the total impact force. The adopted model was
validated by using data from experimental test. In these models a nonlinear materials
behavior for steel plate was simulated using appropriate constitutive model. The
results showed that the general behavior of the finite element models represented by
the mid span deflection - time history curves, maximum mid span deflection, vibration
time of the beams, and residual impact deformation show good agreement with the
experimentally tested specimen. After analyzing the models it was found that by
increasing the thickness of the corrugated steel plate the mid span deflection along
with vibration time will decreases up to (29.3 %) and (45.9 %), respectively. Also,
reduction in total impact force causes the decrease in mid span deflection and
vibration time up to (32.6 %) and (46.12 %), respectively.
Key words: Finite Element Modeling, Corrugated Steel Beams, Impact Load, and
Residual Impact Deformation.
Cite this Article: Mohammad R.K.M. Al-Badkubi, Finite Element Study on Hollow
Corrugated Steel Beams under Impact Loading, International Journal of Civil
Engineering and Technology (IJCIET) 9(10), 2018, pp. 139–152.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=9&IType=10
1. INTRODUCTION
Nowadays almost all industries are redirecting their strategic plans on developing
environmentally friendly products that building and construction industry is not an exempt.
Although numerous research is being conducted to commercialize incorporation of novel
materials in infrastructures applications, structural elements made from steel alloys are yet the
most common ones. This popularity can be due to the high strength to weight ratio attributes
and remarkable fabrication versatility of steel material [1].
Mohammad R.K.M. Al-Badkubi
http://www.iaeme.com/IJCIET/index.asp 140 [email protected]
Corrugated sheets and plates have been used in lots of engineering fields. They have a
several advantages like lightweight, economical, self-strengthen, and easy shipping and
storage process. Hitherto have attracted researcher's interests to broaden their applications,
since they were introduced for the first time.
The corrugated shape provides continuous stiffening for the sheets similar to stiffened
panels, but allows using thinner plates. They can be bent in one direction easily while it
retains its rigidity in the other direction. Furthermore, the fabrication cost of elements with
corrugated panels are normally lower than those with stiffened plates [2-4].
The use of fabricated hollow sections built up from corrugated plates was introduced by
Nassirnia et al. [5] for the first time. The idea was further developed by implementing in
concrete-filled double skin columns [6] and combining with ultra-high strength steel tubes
[7]. Also, the performance of new sections under uniaxial loading was investigated.
During the lifetime of a structure, in addition to bearing quasi-static loads induced by live
and dead loads, it may inevitably suffer from various natural hazards such as impact loads,
earthquakes, and fire [8].
Thus, in this study, A theoretical analysis was performed to predict the behavior
(deflection and impact deformation) of corrugated beams subjected to impact load by using a
nonlinear finite element program (Abaqus 6.14-4). The validity of analytical test results are
compared with experimental test results [1].
2. SPECIMENS DESCRIPTION
This paper represents an analytical study on the behavior of the corrugated steel beams under
impact load. The total number of six corrugated steel beams were tested. The parameters
which are studied are the thickness of the corrugated steel beam and the magnitude of the total
impact force applied on the beams. The detail of the test specimens is shown in Table (1):
Table 1 Specimens Identification.
It is worth noting that the analytical tests are verifying due to comparison of experimental
results and analytical results for beam (CB31), after which the remaining specimens were
tested using the same calibrated model.
3. FINITE ELEMENT MODELING OF THE SPECIMENS
3.1. Modeling of Corrugated Steel Beam
The first step involved in the finite element analysis method consists of building the model. In
this step, the structure is created and then divided intofinite elements connected together at
their nodes. In building a finite element model, it is necessary to define the geometry of the
model, element type and material properties.
Beam
No.
Beam
Symbol
Thickness t
(mm)
Impact force
Factor
1 CB31 3 1
2 CB41 4 1
3 CB61 6 1
4 CB30.5 3 0.5
5 CB40.5 4 0.5
6 CB60.5 6 0.5
Finite Element Study on Hollow Corrugated Steel Beams under Impact Loading
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3.1.1. Selecting Geometry
Generally, a corrugated plates are formed by repeating identical unit profile. The number of
units depends on the application and the target size. In this study, three units (n = 3) are
considered [1]. Also, there are several type of unit corrugation profiles for various
applications. In this study, trapezoidal corrugated unit as shown in Figure (1) is chosen to be
studied [1].
Figure 1 A Trapezoidal Corrugated Unit Profile.
Since unit geometrical dimensions could affect the overall performance of corrugated
beams, the unit profile dimensions are shown in Table (2).
Table 2 Corrugated Unit Profile Dimensions [3].
All of the beam specimens in this study are 1.8 m long and Figure (2) illustrates the
generated finite element model for the corrugated steel beam.
Figure 2 Modeling of Corrugated Steel Beam.
3.1.2. Selecting Element Type
A 4-node shell element S4R (4-node doubly curved general-purpose shell, reduced
integration) is adapted in this study to represent the corrugated steel beam. The shell element
which has displacement and rotation degrees of freedom (6 D.O.F) at each node is shown in
Figure (3). Also, Figure (4) shows the meshed shape of the corrugated steel member.
α (o) a (mm) b (mm) h (mm) d (mm) L (mm) Drawing
45 20 10 15 15 70
Mohammad R.K.M. Al-Badkubi
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Figure 3 Two Dimensional 4-Node Conventional Shell Element [9].
Figure 4 Meshed Shape of Corrugated Steel Beam Model.
3.1.3. Constitutive Model of Steel
The adapted stress-strain relation for structural steel in this study is shown in Figure (5),
where fp , fy and fu are proportional limit, yield stress and ultimate stress of steel respectively.
The plastic deformation of steel in this work is described using the Von Mises yielding
criterion.
Figure 5 Stress-Strain Curve for Steel [10].
During the elastic-plastic stage (a-b), by increase in applied stress, the tangent modulus of
elasticity for steel (Est) decreases from Young’s modulus (Es) to zero (during the yielding
Finite Element Study on Hollow Corrugated Steel Beams under Impact Loading
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stage b-c).Hence, the calculation of (Est) is done by using the formula which proposed by
Bleich in (1952):
(1)
where (σs) is the stress in the steel. Furthermore, the change in steel response to the
applied stresses the Poisson's ratio (µs) also changes by increase of stress at the elastic-
plasticstage. Hence, the Poisson's ratio in this stage is calculated using the following formula
which was proposed by Han in (2004):
(2)
It should be noted that the steel was assumed to have identical properties in tension and
compression. The steel parameters which used in this study are shown in Table (3):
Table 3:Steel Material Properties.
4. BOUNDARY CONDITIONS
In order to obtain a unique solution in analyzing the deformation displacement for the
corrugated steel beams the boundary conditions at beam edges are needed. To make sure that
the FEM model acts similar to the experimental specimen's condition, the boundary
conditions were applied at two edges of the beam[11].
In the experimental system all of the specimens were placed on a supporting steel section
frame as shown in Figure (6). Then the specimens were fastened with bolts inside the frame to
obtain fixed support as much as possible. Also, this configuration of the boundary conditions
restrained any outward deformation. However, any inward deformation could happen since
the specimens have hollow section.
Figure 6 Experimentally applied Boundary Condition [1].
In the analytical system, the experimental boundary conditions was simulated by resting
and bounding the specimens inside a blocked steel section frame. In finite element model a
20-node standard 3D stress reduced integration quadratic hexahedral (brick) element
(C3D20R) was used to represent the steel frame elements. The geometry and node locations
fy (MPa) Es (MPa)
252 200,000
Mohammad R.K.M. Al-Badkubi
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for the element type are shown in Figure (7). The original shape of blocked steel section
frame and the meshed shape of the frame is shown in Figure (8).
Figure 7 20-Node Quadratic Brick Element (C3D20R) [9].
Figure 8 Original and Meshed Shape of Blocked Steel Frame.
The blocked steel frame considered to has fixed supports at its outer surfaces, as shown in
Figure (9). Also, the contact between the specimens and the steel frame was simulated by
using surface to surface contact interaction which defined the inner faces of the frame as
master surface and the outer most surface of the corrugated beam as slave surface with finite
sliding formulation and the contact property was considered to have rough friction
formulation in tangential behavior which do not allow any slip to occur once points are in
contact along with hard contact property that will allow separation of the beams from the
frame when the deformation occurs.
Figure 9 Modeling of the Boundary Condition of the Specimens.
Finite Element Study on Hollow Corrugated Steel Beams under Impact Loading
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5. LOADING SYSTEM
In the finite element modeling, the impact force was modeled by using a steel plate to
simulate the dropped steel hammer. A 20-node quadratic, reduced integration, hexahedral
(brick) element with linear elastic properties for steel material was used to represent the steel
plate. The used element is shown in Figure (7), and the steel plate model is shown in Figure
(10).
Figure 10 Steel Plate Modeling.
To simulate the impact force resulting from modeled steel plate there are two different
approaches which are as following:
1) Subjecting the steel plate to gravitational acceleration during the solution in order to leave
the weight to fall freely. This method recommended to save analysis time by starting at small
distance from the top of steel beam and apply initial velocity according to the shifted distance
[9].
2) Simulating the impact force by a pulse such a rectangular or triangular load function, the
magnitude of maximum impact force and its duration time has to be taken from the
experimental results [9].
In the present study the second method is adopted to simulate the impact force. The
magnitude of impact force and its duration has taken from experimentally tested specimen [1]
and illustrated as a rectangular pulse shown in Figure (11):
Figure 11 Impact Force and Its Magnitude Simulation.
So, for both hammer weight the impact force duration has taken to be (0.03 s) and its
magnitude taken as (1486 KN) and (1243 KN) for normal weight and half weight hammer,
respectively.
The kinetic impact energy was calculated by using the following equation:
Mohammad R.K.M. Al-Badkubi
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(3)
Where (m) is the steel plate (steel hammer) mass (Kg) and (v) is the velocity of drop steel
hammer which is calculated based on the governing velocity formula of a falling object which
is defined as:
(4)
Where (g) is the gravitational acceleration which is about (9.81 m/sce2) and (t) is the
travelling time for dropped steel hammer from the starting height of the fall to impact with the
steel beam.
Also, this time of travel can be calculated if the height of the drop (h) is known using the
following formula:
(
)
(5)
Table (4) shows the kinetic energy calculation results for specimens (1-6):
Table 4 Impact Test Level Definition
6. TIME-DEFORMATIONCURVES
Deformations are measured at mid-span from the upper face of the beam to the lowest
location of the deformed beam.
By comparing the analytical result curve and experimental result curve as shown in Figure
(12), it can be seen that the adapted finite element model is in good agreement with the
experimental results. This good agreement shows that the model can be utilized for some
other cases other than this experimental case. So, the analytical cases mentioned previously
were considered to be investigated.
Figure 12 Comparison of Mid Span Deformation History for FEM CB31 Model and Experimental
Test.
Test No. h (m) m (kg) t (s) v
(m/s)
KE
(kJ)
1-3 7 266.5 1.194 11.7 18.24
6-4 7 133.25 1.194 11.7 9.12
Finite Element Study on Hollow Corrugated Steel Beams under Impact Loading
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From the Figure (12) it can be seen that the finite element deflection curve have about
four pulses of vibration which is more than that obtained from the experimental curve which
leave the beam at rest after about two pulses of vibration. This response of the beam in FEM
shows that in the FEM the computer program can observe the deformation of the model more
adequately from the experimental specimens in this very small time interval. Also, it is may
be due to the other factors which affect the experimental work more than that in the FEM,
such as human error, equipment efficiency, corrugated steel beam making process, etc.
Figure (13) shows the comparison between mid-span deformation history curves for FEM
models with different corrugated steel thicknesses.
Figure 13 Comparison between Mid-Span Deformation History Curves for FEM CB31, CB41 and
CB61 Models.
As it can be seen from Figure (13) by increasing the corrugated steel beam thickness the
mid-span deflection decreases as well as the time period between each pulse ofvibration
decreases that will lead to make the beam at rest much sooner than the beam with smaller
thickness. Furthermore, it shows that the thinner plates response to vibration more than those
of thicker plates which tend to be more resistance to vibration effects.
As it was mentioned previously another factor which investigated in this study is the mass
of the impact force. By reducing the falling steel hammer weight to half the respond of the
corrugated steel beam to this new impact force is shown in following figures.
Figure (14): Comparison between Mid-Span Deformation History Curves for FEM CB31
and CB30.5 Models.
Mohammad R.K.M. Al-Badkubi
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Figure 15 Comparison between Mid-Span Deformation History Curves for FEM CB41 and CB40.5
Models.
Figure 16 Comparison between Mid-Span Deformation History Curves for FEM CB61 and CB60.5
Models.
From Figures (14, 15 and 16) it can be seen that by decreasing the steel hammer weight to
its half original weight, the corrugated steel beams show smaller deflection as mid span as
well as smaller time of vibration which leads the beam to be at rest in shorter time compare to
beams respond to original hammer weight.
As it can be seen from Figure (17) the behavior of steel beams subjected to half weight of
original hammer weight is similar to behavior of the beams subjected to original hammer
weight which is by increasing the corrugated steel beam thickness the mid-span deflection
decreases as well as the time period between each pulse of vibration decreases that will lead
to make the beam at rest in shorter timecompared tothinner steel beams.
Finite Element Study on Hollow Corrugated Steel Beams under Impact Loading
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Figure 17 Comparison between Mid-Span Deformation History Curves for FEM CB30.5, CB40.5 and
CB60.5 Models.
The Finite Element Method (FEM) analysis results for maximum mid-span deflection and
the impact vibration time are shown in Table (5):
Table 5 FEM Test Results.
7. FAILURE DEFORMATION
Figures (18-24)illustrate the corrugated steel beam deformation shape due to the application
of the impact load for tested beams in finite element analysis model as well as experimentally
tested beam.
Figure 18 Residual Failure Deformation for Experimentally Tested CB31 [1].
Beam
No.
Beam
Symbol Δmax (mm)
Vibration Time
(s)
1 CB31 195 0.093
2 CB41 168.87 0.074
3 CB61 137.86 0.0594
4 CB30.5 131.43 0.0592
5 CB40.5 119 0.041
6 CB60.5 105.5 0.032
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Figure 19 Residual Failure Deformation for FEM Tested CB31.
Figure 20 Residual Failure Deformation for FEM Tested CB41.
Figure 21 Residual Failure Deformation for FEM Tested CB61.
Figure 22 Residual Failure Deformation for FEM Tested CB30.5.
Finite Element Study on Hollow Corrugated Steel Beams under Impact Loading
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Figure 23 Residual Failure Deformation for FEM Tested CB40.5.
Figure 24 Residual Failure Deformation for FEM Tested CB60.5.
By comparing the experimental failure shape with finite element failure shape Figures
(18) and (19), it can be seen that the local deformation of the beam due to the applied load as
well as global bent in the beam are very similar. Also, by comparing failure shape of Figures
(19) to (24), it can be seen that when the corrugated steel beam thickness increases the overall
behavior of the beam enhanced due to the increase in steel section strength. This enhancement
make it possible for the beam to utilizes the strength of the whole beam in resisting the
applied impact load and make the load distributed in the whole section rather than just little
area around and under the impact load steel hammer.
8. CONCLUSIONS
In this paper, an analytical study on hollow corrugated steel beams under impact loading is
performed by using a nonlinear finite element computer program (Abaqus).
Based on the results obtained by testing simulated steel beam models, the following
conclusions can be obtained:
1. The general behavior of the finite element models represented by the mid span deflection -
time history curves show good agreement with the experimentally tested result curve.
However, the finite element models tend to be slightly stiffer than the experimental beam in
the linear stage of respond.
2.for normal weight steel hammer by increasing the corrugated steel beam thicknesses from (3
mm) to (4 mm) and (6 mm), the maximum mid-span deflection decreases about (13.4 %) and
(29.3 %), respectively.Also, the vibration time decreases about (20.4 %) and (36.12 %) for
(4mm) and (6mm) respectively compared to (3 mm) beam thickness.
3. for half weight steel hammer by increasing the corrugated steel beam thicknesses from (3
mm) to (4 mm) and (6 mm), the maximum mid-span deflection decreases about (9.4 %) and
Mohammad R.K.M. Al-Badkubi
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(19.72 %), respectively. Also, the vibration time decreases about (30.7 %) and (45.9 %) for
(4mm) and (6mm) respectively compared to (3 mm) beam thickness.
4. By using half weight steel hammer there is reduction in maximum mid span deflection and
vibration time about (32.6 %) and (36.34 %) for beam thickness (3 mm) and about (29.5 %)
and (44.6 %) for beam thickness (4 mm) and about (23.4 %) and (46.12 %) for beam
thickness (6 mm), respectively.
CONFLICT OF INTEREST SATEMENT
On behalf of all authors, the corresponding author states that there is no conflict of interest.
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