Impact damage on fibre-reinforced.pdf
-
Upload
tamer-mostafa-samir -
Category
Documents
-
view
220 -
download
0
Transcript of Impact damage on fibre-reinforced.pdf
-
7/25/2019 Impact damage on fibre-reinforced.pdf
1/16
JOURNAL OF
C O MP O S I TE
MATER IALSArticle
Impact damage on fibre-reinforcedpolymer matrix composite A review
Sandeep Agrawal1, Kalyan Kumar Singh2 and PK Sarkar2
Abstract
As the application of fibre-reinforced polymer composite material continue to increase day by day, so the knowledgeabout the impact behaviour of fibre-reinforced polymer composite structures in the areas such as automotive andaerospace is very much needed. This article attempts a comprehensive review of recent literature in the broaderarea of impact damage. Testing methods and standard parameters as well as discussion of important aspects such asimpactor shape, weight of impactor, velocity of impact, environment in which impact takes place are presented.Furthermore, the damage area, energy absorbed, contact time and many other considerations are discussed. Finally,an effort is made to review the research work by considering all aspects related to impact on such type of compositematerials.
Keywords
Composites, fibre-reinforced polymer, impact damage
Introduction
In present days fibre-reinforced composite materials are
widely used in various engineering applications includ-ing automotive, aviation and engineering structures due
to their lightweight, high stiffness, strength and damp-
ing properties. Air vehicles may be subjected to impact
loads by foreign objects such as debris from runways,
bird strikes or hailstones (during flight). The impact
damage in composite materials may not be detected
sometimes by visual inspection. Such impact-induced
damages occur inside the material and increase after
the onset of small delaminations. In an impact event,
several damage types occur in composite materials such
as matrix cracking, delamination and fibre breakage.
Consequently, the impact behaviour of the laminated
composite materials is an important phenomenon to be
studied.1 The brittle nature of most fibre-reinforced
polymer (FRP) composites accompanying other forms
of energy absorption mechanisms such as fibre break-
age, matrix cracking, debonding at the fibrematrix
interface and especially plies delamination, play
important roles on progressive failure mode and
energy absorption capability of composite structures.
These failure modes under low-velocity impact loading
conditions are strongly dependent on the fibre type,
resin type, lay-up, thickness, loading velocity and
projectile type. For low-velocity impact events, the
usage of pendulums like the ones present in the
Charpy test2
and drop towers or drop weights3
hasbecome standard. The high-energy absorbing capabil-
ities of FRP composite materials are one of the main
factors in their application in automotive and aero-
space structures. They also provide other functional
and economic benefits such as enhanced strength, dur-
ability, weight reduction and hence lower fuel con-
sumption for structural vehicle crashworthiness. FRP
composites are able to collapse in a progressive, con-
trolled manner which results in high specific energy
absorption in the event of crash. Unlike metals and
polymers, the progressive energy absorption of com-
posite structures is dominated by extensive microfrac-
ture instead of plastic deformation.47
1Department of Mechanical Engineering, Hindustan College of Science &
Technology, India2Department Of Mechanical Engineering & Mining Machinery Engineering,
Indian School of Mines, India
Corresponding author:
Sandeep Agrawal, Department of Mechanical Engineering, Hindustan
College of Science & Technology, Farah, Mathura 281122, India.
Email: [email protected]
Journal of Composite Materials
2014, Vol 48(3) 317332
! The Author(s) 2012
Reprints and permissions:
sagepub.co.uk/journalsPermissions.nav
DOI: 10.1177/0021998312472217
jcm.sagepub.com
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
2/16
Impact
In general, impact damage is not considered to be a
threat in metallic structures because of the ductile
nature of the material and the large amount of energy
that can be absorbed. At yield stress, the material may
flow for very large strains at a constant rate before
work hardening, but the composites can fail in a widevariety of modes and contain impact damages visible by
a naked eye which severely reduces the structural dur-
ability of the component. Most composites are brittle
and so they can only absorb energy in elastic deform-
ation and through damage mechanisms, and not via
plastic deformation. The term damage resistance7
refers to the amount of impact damage which is
induced in a composite structure. Most of the impacts
on a composite structure will be in the transverse dir-
ection but due to the lack of through thickness
reinforcement, transverse damage resistance is particu-
larly poor. Interlaminar stresses (shear and tension) are
often the stresses that cause primary failure due to the
low interlaminar strengths. As a result, design failure
strains are used to guard against impact failure, result-
ing in a failure to take advantage of the excellent in-
plane strength and stiffness properties of composites.
Velocity of impact
Impacts are generally classified into three categories as
low-velocity impact, high-velocity impact and some-
times hyper velocity impact, but there is not a clear
transition between categories and authors disagree on
their definition.Sjoblom et al.8 and Shivakumar et al.9 define low-
velocity impact as events which can occur in the range
110 m/s depending on the target stiffness, material
properties and the impactor mass and stiffness.
High-velocity impact response is dominated by stress
wave propagation through the material in which the
structure does not have time to respond, leading to
much localised damage. Boundary condition effects
can be ignored because the impact event is over
before the stress waves have reached the edge of the
structure. In low-velocity impact, the dynamic struc-
tural response of the target is of utmost importance
as the contact duration is long enough for the entire
structure to respond to the impact and in consequence
more energy is absorbed elastically.
Cantwell and Morton10 conveniently classified low
velocity as up to 10 m/s, by considering the test tech-
niques which are generally employed in simulating the
impact event (instrumented falling weight impact test-
ing), Charpy, Izod, etc., whilst, in contrast, Abrate11 in
his review of impact on laminated composites stated
that low-velocity impacts occur for impact speeds of
less than l00 m/s.
Liu and Malvem12 and Joshi and Sun13 suggested
that the type of impact can be classified according to
the damage incurred, especially if damage is the prime
concern. High velocity is thus characterised by penetra-
tion-induced fibre breakage, and low velocity by delam-
ination and matrix cracking.
Davies and Robinson14,15
define a low-velocityimpact as being one in which the through-thickness
stress waveplays no significant part in the stress distri-
bution and suggest a simple model to give the transition
to high velocity. A cylindrical zone under the impactor
is considered to undergo a uniform strain as the stress
wave propagates through the plate, giving the compres-
sive strain as14
ec (Impact velocity/speed of sound in the material)
For failure strains between 0.5% and l%, this
gives the transition to stress wave dominated events
at 1020 m/s for epoxy composites.
Impact tests
To simulate actual impact by a foreign object, a
number of test procedures have been suggested by
many researchers. The initial kinetic energy of the pro-
jectile is an important parameter to be considered, but
several other factors also affect the response of the
structure. A large mass with low initial velocity may
not cause the same amount of damage as a smaller
mass with higher velocity, even if the kinetic energies
are exactly the same.
At the moment, two types of tests are used by most
investigators, although many details of the actual testapparatus may differ. Experimental studies attempt to
replicate actual situations under controlled conditions.
For example, during aircraft takeoff and landing,
debris flying from the runway can cause damage; this
situation, with small high-velocity projectiles, is best
simulated using a gas gun. Another concern is the
impact of a composite structure by a larger projectile
at low velocity which occurs when tools are accidentally
dropped on a structure. This situation is best simulated
using a drop weight tester.
Drop weight testers (Figure 1) are used extensively
and can be of different designs. Heavy impactors are
usually guided by a rail during free fall from a given
height.16 Usually, a sensor activates a mechanical
device designed to prevent multiple impacts after the
impactor bounces backup.
Pendulum-type systems (Charpy impact tests) are
used to generate low-velocity impacts. Pendulum-type
testers consist of a steel ball hanging from a string, or a
heavier projectile equipped with force transducers or
velocity sensors. The Hopkinson-type pressure bar
technique was also used. Ghasemnejad et al.17 used a
Charpy impact device consisting of three main parts of
318 Journal of Composite Materials 48(3)
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
3/16
specimens, anvil where the specimen is free supported
and also a pendulum with a defined mass attached to a
rotating arm pinned at the machine body. The Charpy
impact test rig with a dial and a pendulum is shown in
Figure 2. The dial gives readings of the absorbed energy
by the material during impact test which is measured in
Joules.
Parameters affecting impact damage
The extensive experimental work conducted upto now
created an understanding of the parameters that affect
the initiation and growth of impact damage. Material
properties affect the overall stiffness of the structure
and the contact stiffness and therefore will have a
significant effect on the dynamic response of the struc-
ture. Researchers and practitioners are also interested
in properties of the matrix, the fibres and the fibre
matrix interface which control the initiation and
growth of impact damage. The thickness of the lamin-
ates, the size of the panel and the boundary conditions
are all factors that influence the impact dynamics, sincethey control the stiffness of the target. The characteris-
tics of the projectile including its weight, shape, elastic
properties and incident angles are other parameters to
be considered. The layup, stitching, preload and envir-
onmental conditions are important factors which are to
be given attention.
Projectile characteristics
Impactor shape and weight of impactor play a signifi-
cant role in impact damage. In past research, the most
common impactor shape used has been hemispherical.
However, a dropped tool on a composite panel during
maintenance may not always impact the panel with a
blunt shape such as a hemisphere. Apart from the
common hemispherical impactor, some researchers
have used other impactor shapes such as flat-ended
and conical. These experiments have been conducted
under varying conditions, which make it impossible to
compare the results since there are many parameters
that can affect the impact response of composite lamin-
ates. Research which considered the effect of impactor
shape has predominantly been in the high-velocity
impact field where, for instance, the impact resistance
of armour has led to research into the ballistic limit ofprojectile shapes. However, it is known that specimens
react differently to high-velocity impacts where there is
a localised response compared to low-velocity impacts
where a global response may predominate.
Yang and Cantwell16 investigated the damage initi-
ation in glass fibre (GF) reinforced epoxy plates sub-
jected to low-velocity impact loading by considering the
effect of key parameters such as target size, projectile
diameter and test temperature on damage initiation.
The experimental data have been analysed using
simple energy based and stress-based models. The
results show that the damage initiation threshold
force, Pcrit varies with t3/2where t is the thickness of
the composite. For a given target thickness, the Pcritdoes not exhibit a dependency on the plate diameter
for the range of target geometries. It was also found
that at elevated temperature, the damaged threshold
also follows t3/2 dependency. The damage threshold
varied with projectile diameter with Pcrit increasing
steadily with increasing projectile diameter.
In Mitrevski et al.18, the effects of impactor shape
was investigated using hemispherical, ogival and
conical impactors as shown in Figure 3 on carbon/
Figure 1. The drop-weight impact tower.16
Agrawal et al. 319
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
4/16
epoxy laminates. It was found that the specimens
impacted by the conical impactor absorbed the most
energy and produced the largest penetration depth.
The blunter hemispherical impactor produced the lar-
gest peak force and shortest contact duration. The
damage threshold load was highest for the hemispher-
ical impactor followed by the ogival and conical impac-
tors, respectively.
The residual tensile and compressive strengths of
composite laminates are influenced by the damage
area and mechanisms induced by the impact.11,1924
Different impactor shapes will produce different
damage mechanisms and areas in composite laminates;
hence the residual properties of the material will change
according to the impactor shape. It is, therefore,
important to investigate the effects of different impactor
shapes on the damage resistance and tolerance of com-
posite laminates. Lee et al.25 conducted low-velocity
impact tests on simply supported sheet moulding
compound laminates. Conical, flat, hemispherical and
Figure 2. The Zwick/Roell Charpy test rig: (a) side view and (b) front view.17
Figure 3. (a) Hemispherical tup; (b) ogival tup; and (c) conical tup. 18
320 Journal of Composite Materials 48(3)
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
5/16
semi-cylinder impactors were used to impact specimens
of 2.4 mm thickness at initial impact energy of 54.5 J.
They found that flat and hemispherical impactors pro-
duced similar failure mechanisms and energy dissipa-
tion levels. The semi-cylindrical impactor produced a
vertically propagating crack (i.e. through thickness).
The local indentation induced by the flat and hemi-spherical impactors resulted in an increase in energy
dissipation compared to the semi-cylindrical impactor.
Local penetration was observed from the conical
impactor which resulted in the lowest dissipated
impact energy. They also found that the type of failure
mechanism induced by the impact affected the energy
dissipation capacity of the specimen. Using finite elem-
ent analysis, Kim and Goo26 modelled the effect of
altering the ratio between impactor nose lengths to
impactor radius, where a ratio of one represents a hemi-
spherical impactor, on the impact response of GF rein-
forced plastic (GFRP). The ratios tested were 0.1, 1 and
10. It was found that as the ratio decreased (became
more blunt), the peak force increased and the impact
duration decreased.
Zhou et al.27 applied a quasi-static load to nine-ply,
twill-weave, carbon/epoxy laminates with a nominal
thickness of 2 mm through hemispherical and flat
indentors of two sizes: 8 and 20 mm. The change in
indentor nose shape resulted in a change in failure
mode. For the hemispherical indentor, it was found
for most cases that matrix cracking initiated, followed
by fibre fracture. With the flat indentor, ply shear-out
was found to be the dominant failure mechanism since
stress concentration underneath the indentor spreadinto a greater area. This was also found by Zhou28
who used a flat impactor to impact various types of
GFRP. Under static test conditions, Mines et al.29
found flat and hemispherical impactors produced
larger delamination areas compared to a conical impac-
tor in both woven and z-stitched laminates of varying
thickness. This suggests that damage caused by conical
impactors is more localised, which is supported by the
local penetration found by Lee et al.25 Further research
is done under dynamic conditions to determine whether
the damage areas follow the trend produced under
static conditions by Mines et al.29
The influence of indentor geometry on damage
development in composite materials has been investi-
gated by a number of researchers.30,31 Siow and Shim32
showed that impactors with a small radius of curvature
produce a larger delamination area and greater fibre
breakage than those with a larger radius. Wakayama
et al.31 observed a change in failure mode from fibre
fracture to delamination as the impactor radius was
increased, during drop-weight impact tests on fila-
ment-wound carbon fibre reinforced plastics (CFRP)
pipes. Mitrevski et al.18 investigated the influence of
indentor shape on damage initiation in thin woven
CFRP laminates. They showed that hemispherical
indentors gave a higher peak force and shorter contact
duration than either conical or ogival impactors. The
hemispherical indentor resulted in barely visible impact
damage following a 4 J impact, whereas the sharper
indentors produced permanent indentation andpenetration.
Material properties
Mechanical properties of fibre-reinforced composites
are dependent on the properties of the constituent
materials (type, quantity, fibre distribution and orien-
tation and void content). Beside these properties, the
nature of the interfacial bonds and the mechanisms of
load transfer at the interface also play an important
role. If the building parts of composites differ in phys-
ical form and in chemical composition, only a weak
interaction can be developed at the interface. For
improving the adhesion between the matrix and the
fibres, there are varieties of modification technique
depending on the fibre and matrices type. One of
them is the application of coupling agents, which are
able to establish chemical bonds between the fibre and
the matrix due to their chemical composition. The price
of surface modifier chemicals is one of the key points in
the applicability of reinforced composites.33 Polyesters
could not be applied for technological purposes without
reinforcing because of low strength and brittleness, but
they are intensively used for composite matrices.34,35
The GF composites are the most wide spread amongfibre-reinforced materials due to their favourable mech-
anical and economical characteristics. For industrial
applications, the E- and S-type GFs are the most com-
monly used because they have the most favourable
cost-mechanical property relationships. Thermoset
composites have been applied in 1940s in aircraft indus-
try for the first time. Those materials were laminated
polyester composites, and the first application was the
cover of radar antennas because there was a need for
such non-metallic materials that allowed radio waves
through without distortion. The manufactured parts
were found to have better weight/volume ratio than
the ones made from metallic materials. Since then,
thermoset composites have been applied as construc-
tion materials. Current civil aircraft applications have
concentrated on replacing the secondary structure with
fibrous composites, where the reinforcement material
has either been carbon, glass, Kevlar, or hybrids of
those.36
Several authors have been studying the effect of
composite hybridisation on high-velocity impact behav-
iour.3739 Novak and De Crescente40 showed that the
addition of GF to CFRP and boron/epoxy system
Agrawal et al. 321
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
6/16
could improve the impact strength by a factor of 35.
Crack growth in hybrid fibrous composites was studied
by McColl and Morley.41 It was shown that the stabil-
ity of transverse crack in a very brittle matrix could be
increased substantially by inclusion of a second fibre
component designed specially to increase the work of
fracture of the matrix. Bunsell and Harris42
have shownthat the strips of GFRP incorporated into CFRP
laminates acts as efficient crack stoppers only if the
strip width is greater than a limiting value. This could
indicate that hybrids in which the different types of
fibre were more intimately mixed and not in well-
defined planes would not perform as well in terms of
fracture resistance. The same authors concluded that
the work of fracture by impact and the flexural elastic
modulus of mixed GFRP/CFRP composites are both
simple functions of composition corresponding to a
rule of mixture based on the properties of plain
GFRP and CFRP.43 Jang et al.44 showed that hybridis-
ing graphite composites with additional tough high
strain-to-failure fibres give better damage resistance of
composite structures under impact loading. The
obtained results also imply that the stacking sequence
is a major factor governing the overall energy absorb-
ing capability of the hybrid structure, and the penetra-
tion resistance of hybrid composites appeared to be
dictated by the toughness (strength plus ductility) of
their constituent fibres.45
Laminate thickness, layup and stitching
Target stiffness depends on material properties as wellas on the thickness of the laminate, the layup, its size
and the boundary conditions. The stiffness in the thick-
ness direction has a significant effect on the magnitude
of the maximum contact force which of course will
affect the extent of the damage induced.
The stacking sequence also plays a very important
role on the impact resistance of laminates. In a unidir-
ectional laminate, since the reinforcing fibres are all
oriented in the same direction, no delamination
occurs. For two plates with the same thickness but
with different stacking sequences, the one with the
higher differences of angle between two adjacent plies
will experience higher delamination areas. Increasing
the thickness of each layer will also lead to increased
delaminations. Increasing the difference between the
longitudinal and transverse moduli of the material
leads to higher bending stiffness mismatching and
therefore increased delaminations. However, damage
initiation is matrix- and interface-dependent and there-
fore has little or no dependence on the stacking
sequence. The peak load reached during impact or the
energy at peak load is strongly dependent on the stack-
ing sequence.11
Stitching is used to introduce through the thickness
reinforcement but in a different way than with weaving
or braiding. The laminated structure is preserved and
stitching can be performed on either a prepeg or pre-
form. Stitching density and pattern and properties of
the thread can be varied to improve delamination
resistance.Sadasivam and Mallick46 have studied the low-
energy impact characteristics of four different E-GF
reinforced thermoplastic and thermosetting matrix
composites. Low-energy impact caused dent on the
impacted side and surface cracks on the unimpacted
side of all four composites. The damage size, maximum
impact load, deflection at the maximum load and tup
velocity dissipation of the four composites are com-
pared. The residual tensile strength of the impact-
damaged composites is also determined as a function
of the input impact energy.
Caprino et al.47 have performed low-velocity impact
tests on carbon/epoxy laminates of different thick-
nesses. They have examined the force and absorbed
energy at the onset of delamination, the maximum
force and related energy and penetration energy.
From the experimental results, all these quantities,
except the energy for delamination initiation, followed
the same trend, increasing to the power of approxi-
mately 1.5 with increasing plate thickness. Some experi-
mental investigations have been carried out by Hosur
et al.48 to determine the response of four different com-
binations of hybrid laminates subjected to low-velocity
impact loading. They have indicated that there was
considerable improvement in the load-carrying capabil-ity of hybrid composites as compared to carbon/epoxy
laminates with slight reduction in stiffness. Datta
et al.49 have investigated the effects of variable impact
energy and laminate thickness on the low-velocity
impact damage tolerance of GFRP composite lamin-
ates. Critical values of impact energy and laminate
thickness were also defined. Baucom and Zikry50 have
conducted an experimental study to understand the
effects of reinforcement geometry on damage progress
in woven composite panels under repeated impact load-
ing. The composite systems included a two-dimensional
(2D) plain-woven laminate, a 3D orthogonally woven
monolith, and a bi-axially reinforced warp-knit. The
radial spread of damage was smallest for the 2D lamin-
ates and largest for the 3D woven composites. The 3D
composites had the greatest resistance to penetration
and dissipated more total energy than the other sys-
tems. Fuoss et al.51,52 have worked on the effects of
key stacking sequence parameters on the impact
damage resistance in composite laminates. A finite
element model using linear, quasi-static analysis
was developed to analyse the internal stress state
in the laminate and predict delamination damage.
322 Journal of Composite Materials 48(3)
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
7/16
A parameter based on bending strain is proposed as a
method of predicting the impact damage resistance in a
composite laminate with respect to changes in stacking
sequence. The method was evaluated by ranking lamin-
ates for damage resistance using the proposed param-
eter and comparing the results with existing
experimental and numerical results. The results weregenerally positive, as the damage resistance parameter
had a high linear correlation with the experimentally
measured or numerically predicted damage areas.
Rydin et al.53 have investigated the influence of
impact velocity on woven and non-woven composites.
For the range of impact velocities attainable in a typical
drop weight impact tower (
-
7/25/2019 Impact damage on fibre-reinforced.pdf
8/16
behaviour of glass/epoxy laminated composite plates
under low-velocity impact theoretically and experimen-
tally. Tita et al.69 have conducted experimental and
numerical studies to examine the stacking sequence
and impact energy effect on thin carbon/epoxy lami-
nated composite plates under low-velocity impact.
The influence of stacking sequence and energy impactwas investigated using loadtime histories, displace-
menttime histories and energytime histories as well
as images from NDE. Indentation tests results were
compared to dynamic results, verifying the inertia
effects when thin composite laminate was impacted by
foreign object with low velocity. For the experimental
approach, it is verified that stacking sequence and
impact energy level can influence the dynamic response
of composite plates. The graphs of forcetime and
energytime, as well as the images fromultrasonic
C-scan technique are used in order to compare the
mechanical behaviour of the specimens. The indenta-
tion test can be used to represent a drop-test when the
impact energy level is low and the specimen has a quasi-
elastic behaviour. Because the indentation curves do
not show the oscillations inherent in the dynamic
response obtained in drop-tests, there is more failure
mechanisms activated during the impact event than in
quasi-static event. Besides, the failure mechanisms
shown by the impact event are more distributed and
with a quasi-static event they are more concentrated.
Thus, the structural global stiffness reduces with more
intensity for drop-test. Finally, it is very important to
comment that the experimental test results for this
study were used to validate and calibrate a compositematerial failure model developed by the authors. Li
et al.70 have done an experimental and numerical inves-
tigation on low-velocity impact-induced damage of
continuous fibre-reinforced composite laminates.
Results show that the maximum contact force decreases
while the maximum deflection increases with increasing
of the plate thickness. In addition, the influence of the
boundary condition on the maximum contact force,
maximum deflection and delamination size is very
small. However, the impactor mass has a significant
effect on the impact behaviour of the composite plates.
Preload
Many researchers have analytically and experimentally
investigated the low-velocity impact behaviour of com-
posite laminated structures.70 Most composite struc-
tures will be under some level of stress when
impacted. For example, the upper layer of the main
wing of the aircraft will be mainly under in-plane com-
pressive load during flight and the lower one will be
under in-plane tensile load. So, foreign objects like
hail and debris in the runway shall give an impact to
composite laminated structure under in-plane load.
Very often, a composite structure experiences impact
loading in addition to the pre-existing stresses produced
either by service loads or by manufacturing/assembly
process. A common example is that of the structure of
an aircraft which during flight may experience bird-hit,
etc., while it is highly stressed due to various serviceloads. However, not much literature is available on
the impact response of composite structures with
prestresses.
Chen and Sun71 have developed a finite element pro-
gram to analyse the impact response of the composite
laminate under biaxial in-plane load. Using the finite
element program, they solved for three cases of in-plane
load, tension/tension load of three times of critical
buckling load of the plate, compression/compression
load of 75% of the critical bucking load and no initial
in-plane load. The impact condition is the case that the
mass of the impactor is very small and the impact vel-
ocity is very high. They concluded that the initial tensile
in-plane load tends to intensify the contact force while
reducing the contact time and an opposite conclusion is
obtained for an initial compressive in-plane load.
Except for this study, it is very rare to find another
analytical result on the impact behaviour of the com-
posite laminates under in-plane load. Kelkar et al.72
reported an experimental and analytical result on the
impact behaviour and the damage area through drop-
weight type impact test, which includes three cases of
thickness of the laminate (16, 32 and 48 plies) and four
cases of tensile in-plane load (0, 800, 1600 and 2400 me).
Their experimental result showed that as the initial in-plane load increases, the impact duration decreases and
the impact load increases. Also, it was observed that as
the initial in-plane load increases, in the case of 16-ply
laminates, the damage area increases. However, in the
case of 32-ply thick laminates, there was a marginal
increase in the damage area. In the case of 48-ply
thick laminates, for lower impact energy, there was a
marginal increase in the damage area. However, for
larger impact energy, there was a reduction in the
damage area. They tried an analytical prediction of
the damage area from quasi-static solution using com-
mercial finite element analysis software, but detailed
numerical output could not be found.72 Mitrevski
et al.73 presented the experimental results on the
impact behaviour of carbon/epoxy and glass/polyester
composite. They concluded that as the initial tensile in-
plane load increases, the contact duration decreases;
however, the initial tensile in-plane load has not
affected the maximum contact force and the damage
area. An experimental investigation on this aspect of
composite structures has been recently carried out by
Whittingham et al.74 In this study, laminated plates of
carbon fibre reinforced composites were subjected to
324 Journal of Composite Materials 48(3)
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
9/16
low-velocity impact while uniaxial or biaxial prestresses
already existed in the plane of the plates. Both tensile
and compressive preloads were used and impacts of two
magnitudes (measured in terms of impact energy) were
produced. It was shown that at low-impact energy, the
indentation depth and the peak load are independent of
the nature and magnitude of prestresses. Robb et al.75
investigated the damage phenomenon and damage tol-
erance of chopped strand matt laminates under impact
loading in the presence of uniaxial and biaxial pres-
tresses. It is observed that the shape, orientation and
size of the damage zone is strongly influenced by the
nature and magnitude of the prestrain. Impact speci-
mens subject to shear loading exhibit the largest
increase in damage area when compared to unstressed
plates.
Environmental conditions
A few researchers have also showed the effect of envir-
onmental aspects on impact damage such as low tem-
perature, UV rays, etc. Because most composite
structures are used outdoors, it cannot be avoided
that composite structures are subjected to various
environmental conditioning. The study of impact and
post impact response of laminated composites sub-
jected to environmental conditioning other than ambi-
ent is more realistic. Karasek et al.76 have evaluated the
influence of temperature and moisture on the impact
resistance of an epoxy/graphite composite. They have
found that only at elevated temperatures, the moisture
had a significant effect on damage initiation energy andthat the energy required for initiating damage had been
found to decrease with temperature. The investigations
by Bibo et al.77 have shown that temperature is capable
of altering the nature and extent of impact induced
damages. Parvatareddy et al.78 have investigated the
low-velocity impact behaviour of laminated composites
aged at elevated temperature in both air and nitrogen
environments. They have indicated that the ageing
environment has a significant effect on the residual ten-
sile strength. Hale et al.79 have found that the effect of
temperature and moisture is interactive. The loss of
strength and stiffness of laminated composites at ele-
vated temperatures is exacerbated by the increased rate
of water absorption at high temperatures. Li et al.80
have investigated the effect of cycling moisture on the
low-velocity impact behaviour of laminated composites
at elevated temperatures. Their results show that the
first moisture cycle has a significant effect on reducing
the low-velocity impact resistance of laminated com-
posites. Elevated temperature accelerates the damaging
effect of cycling moistures. Pang et al.81 have investi-
gated the effect of ultraviolet radiation on the low-
velocity impact response of laminated beams.
They have found that UV radiation alone has a signifi-
cant effect on reducing the residual load-carrying cap-
acity of impact damaged laminated beams. The
presence of water increased the damage effect of UV
radiation. Ibekwe et al.82 investigated low-velocity
impact response and post-impact compression buckling
strength of GF reinforced unidirectional and cross-plylaminated composite beams at low temperatures and
showed that the temperature has a significant effect
on the low-velocity impact responses of laminated com-
posites. More impact damage is induced in specimens
impacted at lower temperatures than those at higher
temperatures. The residual compressive buckling
strength and elastic modulus increase until a certain
point as temperature drops, at a much lower tempera-
ture both the residual compressive buckling strength
and the elastic modulus drop. It was also found that
the impact damage and the temperature have an oppos-
ite effect on the residual compressive buckling strength
and elastic modulus. The impact damage reduces the
residual compressive strength while the low tempera-
ture tends to increase it. Salehi-Khojin et al.83 investi-
gated the role of temperature on impact properties of
Kevlar/fibreglass composite laminates. In this investi-
gation, impact energy level and temperature were found
to have significant effects on the impact behaviour of
fibreglass and combinations of fibreglass with Kevlar.
At low impact energy, the amount of maximum
absorbed energy is almost constant and independent
of temperature. With increasing energy level, absorbed
energy becomes more and more dependent on tempera-
ture. At each of the impact energies, maximum deflec-tion is a function of impact energy and temperature
such that maximum deflection increases with a corres-
ponding increase in impact energy or temperature.
A few studies have focused on the effect of tempera-
ture on the impact response of polymer matrix compos-
ites. A decrease in delamination area was reported84
with increase in temperature in the range between
40C and 70C for a carbon fibre composite laminate
subjected to high energy impact. In a similar high-
velocity impact study on cross-ply laminates of poly-
ethylene fibre/epoxy matrix system,85 it was found that
the damage initiation energy doubled when the tem-
perature was increased from 50C to 100C. In con-
trast, laminates containing plain-weave fabrics showed
very little influence of temperature on the total impact
energy required for complete penetration of the speci-
men. Son and Kwon Young86 studied the effect of tem-
perature variation (30C to 120C) on damage to
orthotropic CFRP laminates at non-penetrating
impact velocities (upto 100 m/s). They observed a
linear relationship between the impact energy and the
delaminated area as well as an increase in the damage
area as the temperature decreased.
Agrawal et al. 325
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
10/16
Damage initiation
Impact damage usually follows some very complex dis-
tributions and it may not be possible to reconstruct the
entire sequence of events leading to a given damage
state. For low-velocity impact damage starts with the
creation of a matrix crack. In some cases, the target is
flexible and the crack is created by tensile flexural stres-ses in the bottom ply of laminate, this crack, which is
usually perpendicular to the plane of the laminate, is
called a tensile crack.2 For thick laminates, cracks
appear near the top of the laminate and are created
by the contact stresses. These cracks, called shear
cracks,2 are inclined relative to the mid-plane. Matrix
cracks induce delaminations at interfaces between adja-
cent plies and initiate a pattern of damage evolution
either from the bottom up or from the top down.
Therefore, while it is possible to predict the onset of
damage, a detailed prediction of the final damage
state cannot realistically be achieved.
Two types of approaches are used for predicting
impact damage. The first approach is aimed at predict-
ing the overall damage size. It is based on the premise
that delaminations, which are the critical component of
impact damage, grow because of high transverse shear
stresses in the vicinity of the impactor. The idea is to
determine the distribution of the transverse shear force
resultant around the point of impact and to use an
appropriate failure criterion to estimate the size of the
damage zone.
The second approach to be discussed here deals with
the prediction of the threshold value of the contact
force that corresponds to damage initiation. When thedamage area is plotted versus the maximum impact
force, there is a clear sudden increase in damage size
once the load reaches a critical value Pcrit. Below this
critical value, the damage area is small due to Hertzian
surface (a surface according to Hertz contact law) and
Pcrit corresponds to the onset delaminations.2
Under low-velocity impact loading conditions, the
time of contact between projectile and target are rela-
tively long. The load history can yield important infor-
mation concerning damage initiation and growth.8791
Several investigators used the force history to compare
the structural response from impact tests. As pointed
out in the literature, the first load drop, in terms of
Hertzian failure or significant damage corresponds to
the occurrence of initial damage in the form of matrix
cracking, fibre breakage and local puncture or indenta-
tion.8996 Davies and Zhang88 pointed out that the first
damage threshold is probably due to the initialisation
of delamination failure. Belingardi and Vadori91
defined two thresholds from the load history. The first
one was at the first load drop for the first material
damage and the second one was the maximum force
value for the first lamina failure.
Davies et al.87 proposed an equation for a critical
force threshold
P2crit 82Eh3GIIc=91v
2
wherePcritis the threshold load, Eand the equivalent
in-plane modulus and Poisson ratio, h the laminatethickness and GIIc the critical strain energy release
rate. The model indicates that the square of the critical
force threshold is proportional to the cube of the lamin-
ate thickness. The predictions from this equation for
delamination initiation agreed well with their experi-
mental data.88,89 Sjoblom97 also predicted that the crit-
ical damage initiation load should increase with t3/2.
However, some results showed that the delamination
threshold load varied with the laminate thickness to
the 3/2 power.90,97 Fibre failure occurs under the
impactor due to locally high stresses and indentation
effects. Belingardi and Vadori91 define a term of satur-
ation impact energy, which is the maximum energy
bearable by the material without perforation.
Dorey98 gives a simple equation for the energy
required for fibre failure and for penetration
E 2wtL=18Ef
whereis the flexural strength,Efthe flexural modulus,
w the width, L the unsupported length and t the speci-
men thickness.
Aktas et al.99 presented a schematic illustration for
different damage modes in composite laminates, as
shown in Figure 4.
Damage propagation
When a solid is subjected to any kind of loading, static
or impact, it can absorb energy by two basic mechan-
ism creations of new surfaces and material deform-
ation. The material deformation occurs first. If the
energy supplied is large enough, a crack may initiate
and propagate, thus actuating the second energy-
absorbing mechanism. The material deformation
continues in advance of the crack during crack propa-
gation. In the case of brittle materials such as glass and
other ceramics only a small amount of deformation
takes place. The associated energy absorbed is also
small. As a consequence, brittle materials exhibit a
low energy absorption capability.
Impact energy (Ei) and absorbed energy (Ea) are two
main parameters that can be used to assess damage
propagation in composite structures after an impact
event. Ei can be defined as the kinetic energy of the
impactor right before contactimpact takes place
while Ea is termed as the amount of energy absorbed
by the composite specimen at the end of an impact
326 Journal of Composite Materials 48(3)
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
11/16
event. Absorbed energy can be calculated from load
deflection (Fd) curves. Figure 5 shows two typical Fd
curves encountered in an impact event. Shaded areas in
Figure 5(a) and (b) represent the energies absorbed by
specimens during impact tests resulting in closed- and
open-type curves, respectively. Open-type Fd curves
have a horizontal section at the very end, post-
perforation frictional section. In order to identify the
true energy absorption due to damage formation in the
specimens, the post-perforation frictional sections need
to be removed from the curves.100 For this purpose, the
ending part of the descending section of the Fdcurve
may be extended to the deflection axis, shown as the
dashed line in Figure 5(b).
Karakuzu et al.101 plotted the impact energy versus
the absorbed energy for equal mass and equal velocity
as shown in Figure 6 using energy profiling dia-
grams.59,61 That is, variation of the absorbed energy
versus impact energy is plotted for two equal param-
eters; mass and velocity. It is clearly observed from
Figure 6 that all the specimens are of the rebounding
case. However, the specimen subjected to 40 J for equal
Figure 4. Schematic illustrations for different damage modes.99
Figure 5. Calculation of the absorbed energy from loaddeflection curves for a non-perforated specimen (a) and a perforated
specimen (b).100
Agrawal et al. 327
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
12/16
velocity has reached the penetration threshold. In add-
ition, the energy absorption capability of the specimen
subjected to equal mass is lower than the specimen sub-
jected to equal velocity, for the same impact energy.
They have carried out an experimental and numer-
ical study to investigate the effect of the equal impact
energy (40 J), equal impactor mass (5 kg) and equal vel-
ocity (2 m/s) on the contact force, deflection, contact
time, damage area and absorbed energy of glass/
epoxy laminated composite plates by taking the orien-
tation [0/30/60/90]s. The equal impact energy
remained constant by changing the impact velocity or
the impactor mass. The numerical analysis was done
using 3DIMPACT finite element code. Results show
that the energy absorption capability of the specimens
subjected to equal mass is lower than the specimens
Figure 6. Energy profiling diagram for the experimental results.101
Figure 7. The variation of impact energy versus (a) maximum contact force, (b) maximum deflection and (c) contact time dependingon the equal mass and the equal velocity.101
328 Journal of Composite Materials 48(3)
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
13/16
subjected to equal velocities and the effects of the equal
mass and the equal velocity on the maximum contact
force and maximum deflection are nearly the same
while the impact energy increases. For a better under-
standing of the impact behaviour of glass/epoxy com-
posite plates, only the maximum values of the contact
force, maximum deflection and contact time are shownin Figure 7. As observed from the figure, the equal mass
and the equal velocity have nearly the same effects on
the maximum contact force and maximum deflection
while the impact energy increases (Figure 7(a) and
(b)). However, the effect of both on the contact time
differs from each other (Figure 7(c)).
The various mechanisms involved during crack
propagation account for the total energy absorbed in
a fracture process. Obviously, the same mechanisms
will not be important in all combinations of matrix
and fibre materials. No single mechanism can account
for the observed toughness of composites. The various
failure mechanisms are fibre breakage, matrix deform-
ation and cracking, fibre debonding, fibre pullout and
delamination cracks.
Spall strength of GFs reinforced epoxy composites
were measured by Zaretsky et al.102 It was found that
three possible failure modes as debonding, delamin-
ation and matrix cracking for the composite resulted
in large variations of the spall strength. A nucleation
and growth model together with a fracture model that
were applied by Tokheim et al.,103 provided good esti-
mates for corresponding experimental measurements of
spall strength in a Kevlar fibres reinforced epoxy com-
posite. Delamination strength of GFs reinforced com-posites were measured by Dandekar et al.104 under
plane normal and oblique impact conditions. A thresh-
old shock-induced compression stress beyond which
delamination will occur due to refracted tensile waves
was determined. The values of the threshold and delam-
ination tensile stresses were found to depend strongly
on the angle of the impact relative to the fibres plane.
Syam et al.105 examined the fracture mechanism in rein-
forced plastics. It was found that the damage zone con-
sisted of matrix cracking, fractured fibres and
debonding between the fibres and the matrix.
Conclusion
There has been a growing interest, particularly in the
past few decades, in the use of composite materials in
structural applications ranging from aircraft and space
structures to automotive and biomedical applications.
However, their behaviour under impact loading is one
of the major concerns, since impacts do occur during
manufacture, normal operations, maintenance, etc.
Especially, unidirectional laminated plates are highly
susceptible to the transverse impact loads resulting in
significant damages such as matrix cracks, delamin-
ations and fibre fractures. Numerous studies on the
impact response of composite materials and structures
can be found in review papers.
Low-velocity impact refers to impacts in the range
110 m/s which are ordinarily introduced in the labora-
tory by mechanical test machines. The contact period issuch that the whole structure has time to respond to the
loading. The modes of impact damage induced range
from matrix cracking and delamination through to
fibre failure and penetration. Damage mode interaction
must also be understood when attempting to predict
initiation and propagation of a particular form of
damage. Toughened resins or thermoplastics can
reduce matrix-dominated damage but the fibres have
the most bearing on impact response and over the
narrow velocity range under consideration, the strain
rate sensitivity of fibres can be ignored. Post-impact
performance is related to the major damage mode;
therefore, a combination of tension and compression
residual strength testing is required to characterise the
laminate.
Polymer-matrix composites are known to be highly
susceptible to internal damage caused by transverse
loads even under low-velocity impacts. The composites
can be damaged on the surface. They can also be
damaged beneath the surface by relatively light impacts
causing barely visible impact damage, while the surface
may appear to be undamaged to visual inspection. For
the effective use of polymer-matrix composites for high-
performance applications, understanding the causes
of the formation of such damage when subjected tolow- and high-velocity impact and improving the
damage-resistance characteristics of the composites are
important considerations. Vast research has been per-
formed on simple geometry carbon/epoxy cross-ply
laminates consistingof plies at various fibre orientations,
due to their importance in the aerospace industry. The
low-velocity impact response of random fibre/unidirec-
tional laminate combinations and impacts on complex
geometry are less well documented, and more research
work is required in these areas if composite laminates are
to be employed in more structural applications.
Funding
This research received no specific grant from any funding
agency in the public, commercial, or not-for-profit sectors.
Conflict of interest
None declared.
References
1. Erbil E. Impact loading in laminated composites. MSc
Thesis, DokuzEylu l University, Turkey, 2008.
Agrawal et al. 329
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
14/16
2. Abrate S. Impact on composites structures. Cambridge:
Cambridge University Press, 1998.
3. Richardson MOW and Wisheart MJ. Review of low-
velocity impact properties of composite materials.
Composites Part A 1996; 27A: 11231131.
4. Hull D. A unified approach to progressive crushing of
fibre reinforced tubes. Compos Sci Technol 1991; 40:
377421.5. Farley G and Jones R. Crushing characteristics of con-
tinuous fibre reinforced composite tubes. J Compos
Mater 1992; 26: 3750.
6. Fairfull A and Hull D. Energy absorption of polymer
matrix composite structures: frictional effects.
In: Wierzbicki T and Jones D (eds) Structural failure.
New York: John Wiley and Sons, 1989, pp.255279.
7. Mamalis AG, Manolakos DE, Demosthenous GA, et al.
The static and dynamic collapse of fibre glass composite
automotive frame rails. Compos Struct 1996; 34: 7790.
8. Sjoblom PO, Hartness JT and Cordell TM. On low-
velocity impact testing of composite materials.
J Compos Mater 1988; 22: 3052.9. Shivakumar KN, Elber W and Illg W. Prediction of low
velocity impact damage in thin circular laminates. AIAA
J1985; 23(3): 442449.
10. Cantwell WJ and Morton J. The impact resistance of
composite materials a review. Composites 1991; 22(5):
347362.
11. Abrate S. Impact on laminated composite materials.Appl
Mech Rev 1991; 44(4): 155190.
12. Liu D and Malvem LE. Matrix cracking in impacted
glass/epoxy plates. J Compos Mater 1987; 21: 594609.
13. Joshi SP and Sun CT. Impact-induced fracture initiation
and detailed dynamic stress field in the vicinity of impact.
In: Proceedings of American Society of Composites 2nd
technical conference, Newark, DE, 2325 September1987, pp. 177185.
14. Robinson P and Davies GAO. Impactor mass and speci-
men geometry effects in low velocity impact of laminated
composites. Int J Impact Eng 1992; 12(2): 189207.
15. Davies DAO and Robinson P. Predicting failure by
debonding/delamination. In: AGARD: 74th structures
and materials meeting, Patras, Greece, 2529 May 1992.
16. Yang FJ and Cantwell WJ. Impact damage initiation in
composite materials. Compos Sci Technol 2010; 70:
336342.
17. Ghasemnejad H, Furquan ASM and Mason PJ. Charpy
impact damage behaviour of single and multi delami-
nated hybrid composite beam structures. Mater Des
2010; 31: 36533660.
18. Mitrevski T, Marshall IH, Thomson R, et al. The effect
of impactor shape on the impact response of composite
laminates. Compos Struct 2005; 67: 139148.
19. Caprino G. Residual strength prediction of impacted
CFRP laminates. Compos Mater 1984; 18: 508518.
20. Davies GAO, Hitchings D and Zhou G. Impact damage
and residual strengths of woven fabric glass/polyester
laminates. Composite Part A 1996; 27A: 11471156.
21. Cantwell WJ and Morton J. Comparison of the low and
high velocity impact response of CFRP.Composites1989;
20(6): 545551.
22. Prichard JC and Hogg PJ. The role of impact damage in
post-impact compression testing. Composites 1990; 21(6):
503509.
23. Hitchen SA and Kemp RMJ. The effect of stacking
sequence on impact damage in a carbon fibre/epoxy com-
posite. Composites 1995; 26(3): 207214.
24. Benzeggagh ML and Benmedakhene S. Residual strength
of a glass/polypropylene composite material subjected toimpact. Compos Sci Technol1995; 55: 111.
25. Lee SM, Cheon JS and Im YT. Experimental and numer-
ical study of the impact behavior of SMC plates. Compos
Struct 1999; 47: 551561.
26. Kim SJ and Goo NS. Dynamic contact responses of lami-
nated composite plates according to the impactors
shapes. Compos Struct 1997; 65(1): 8390.
27. Zhou G, Lloyd JC and McGuirk JJ. Experimental evalu-
ation of geometric factors affecting damage mechanisms
in carbon/epoxy plates. Composites Part A 2001; 32:
7184.
28. Zhou G. Damage mechanisms in composite laminates
impacted by a flat-ended impactor. Compos Sci Technol1995; 54: 267273.
29. Mines RAW, Roach AM and Jones N. High velocity
perforation behaviour or polymer composite laminates.
Int J Impact Eng 1999; 22: 561588.
30. Zhou G. Prediction of impact damage thresholds of glass
fibre reinforced laminates. Compos Struct 1995; 31:
185193.
31. Wakayama S, Kobayashi S, Imai T, et al. Evaluation of
burst strength of FW-FRP composite pipes after impact
using pitch-based low-modulus carbon fibre. Composites
Part A 2006; 37: 20022010.
32. Siow YP and Shim VPW. An experimental study of low
velocity impact damage in woven fibre composites.
J Compos Mater 1998; 32: 11781202.33. Varga Cs, Miskolczi N, Bartha L, et al. Improving the
mechanical properties of glass-fibre reinforced polyester
composites by modification of fibre surface. Mater Des
2010; 31: 185193.
34. Skrifvars M, Mackin T and Skagernerg B. An application
of experimental design to the development of glass fibre
reinforced polyester laminates with enhanced mechanical
properties. Polym Test 1998; 17(5): 345356.
35. Bagherpour S, Bagheri R and Saatchi A. Effects of con-
centrated HCl on the mechanical properties of storage
aged fibre glass polyester composite. Mater Des 2009;
30: 271274.
36. Soutis C. Carbon fibre reinforced plastic in aircraft con-
struction. Mater Sci Eng A 2005; 412(12): 171176.
37. Marom G, Fischer S, Tuler FR, et al. Hybrid effects in
composites: conditions for positive or negative effects
versus rule-of-mixture behavior. J Mater Sci 1978; 13:
14191426.
38. Zweben C. Tensile strength of hybrid composites.
J Mater Sci1977; 12: 13251337.
39. Manders PW and Bader MG. The strength of hybrid
glass/carbon fibre composites. J Mater Sci 1981; 16:
22332245.
40. Novak RC and De Crescente MA. Impact behavior of
unidirectional resin matrix composites tested in the fibre
330 Journal of Composite Materials 48(3)
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
15/16
direction. In: Composite materials: testing and design
(second conference), ASTM-STP 497, Anaheim, CA,
2022 April 1971, pp.311323, 1971.
41. McColl IR and Morley JG. Crack growth in hybrid
fibrous composites. J Mater Sci1977; 12: 11651175.
42. Bunsell AR and Harris B. Hybrid carbon and glass fibre
composites. Composites 1974; 5: 157164.
43. Harris B and Bunsell AR. Impact properties of glass
fibre/carbon fibre hybrid composites. Composites 1975;
7: 197201.
44. Jang BZ, Chen LC, Wang CZ, et al. Impact resistance
and energy absorption mechanisms in hybrid composites.
Compos Sci Technol1989; 34: 305335.
45. Muhi RJ, Najim F and de Moura MFSF. The effect of
hybridization on the GFRP behavior under high velocity
impact. Composites Part B 2009; 40: 798803.
46. Sadasivam B and Mallick PK. Impact damage resistance
of random fibre reinforced automotive composites.
J Thermoplast Compos Mater 2002; 15: 181191.
47. Caprino G, Lopresto V, Scarponi C, et al. Influence of
material thickness on the response of carbonfabric/epoxy panels to low velocity impact. Compos Sci
Technol1999; 59: 22792286.
48. Hosur MV, Adbullah M and Jeelani S. Studies on the
low-velocity impact response of woven hybrid compos-
ites. Compos Struct 2005; 67: 253262.
49. Datta S, Krishna AV and Rao RMVGK. Low velocity
impact damage tolerance studies on glassepoxy lamin-
ates effects of material, process and test parameters.
J Reinf Plast Compos 2004; 23(3): 327345.
50. Baucom JN and Zikry MA. Low-velocity impact damage
progression in woven E-glass composite systems.
Composite Part A 2005; 36(5): 658664.
51. Fuoss E, Straznicky PV and Poon C. Effects of stacking
sequence on the impact resistance in composite laminates
Part 1: parametric study. Compos Struct 1998; 41:
6777.
52. Fuoss E, Straznicky PV and Poon C. Effects of stacking
sequence on the impact resistance in composite laminates.
Part 2: prediction method. Compos Struct 1998; 41:
177186.
53. Rydin RW, Bushman MB and Karbhari VM. The influ-
ence of velocity in low velocity impact testing of compos-
ites using the drop weight impact tower. J Reinf Plast
Compos 1995; 14: 113127.
54. Kim J-K and Sham M-L. Impact and delamination fail-
ure of woven fabric composites. Compos Sci Technol
2000; 60: 745763.55. Naik NK, Sekher YC and Meduri S. Polymer matrix
woven fabric composites subjected to low velocity
impact: Part IIeffect of plate thickness. J Reinf Plast
Compos 2000; 19: 10311055.
56. Naik NK, Borade SV, Arya H, et al. Experimental stu-
dies on impact behavior of woven fabric composites:
effect of impact parameters. J Reinf Plast Compos 2002;
21: 13471362.
57. Atas C and Dahsin L. Impact response of woven com-
posites with small weaving angles. Int J Impact Eng 2008;
35(2): 8097.
58. Liu D. Characterization of impact properties and damage
process of glass/epoxy composite laminates. J Compos
Mater 2004; 38: 14251442.
59. Liu D, Raju BB and Dang X. Impact perforation resist-
ance of laminated and assembled composite plates. Int J
Impact Eng 2000; 24(6): 733746.
60. Symons DD. Characterisation of indention damage in 0/
90 lay-up T300/914 CFRP. Compos Sci Technol 2000;60(3): 391401.
61. Aktas M, Atas C, Icten BM, et al. An experimental inves-
tigation on impact response of unidirectional composite
laminates. Compos Struct 2009; 87(4): 307313.
62. Icten BM, Atas C, Aktas M, et al. Low temperature effect
on impact response of quasi-isotropic glass/epoxy lami-
nated plates. Compos Struct 2009; 91: 318323.
63. Freitas M, Silva A and Reis L. Numerical evaluation
of failure mechanisms on composite specimens subjected
to impact loading. Composite Part B 2000; 31(3):
199207.
64. Zhang Y, Zhu P and Lai X. Finite element analysis of
low-velocity impact damage in composite laminatedplates. Mater Des 2006; 27: 513519.
65. Olsson R, Donadon MV and Falzon BG. Delamination
threshold load for dynamicimpact on plates. Int J Solids
Struct 2006; 43(10): 31243141.
66. Aslan Z, Karakuzu R and Okutan B. The response of
laminated composite plates under low-velocity impact
loading. Compos Struct 2003; 59(1): 119127.
67. Tiberkak R, Bachene M, Rechak S, et al. Damage pre-
diction in composite plates subjected to low velocity
impact. Compos Struct 2008; 83(1): 7382.
68. Mili F and Necib B. Impact behavior of cross-ply lami-
nated composite plates underlow velocities. Compos
Struct 2001; 51(3): 237244.
69. Tita V, Carvalho J and Vandepitte D. Failure analysis oflow velocity impact on thin composite laminates: experi-
mental and numerical approaches. Compos Struct 2008;
83(4): 413428.
70. Li CF, Hu N, Cheng JG, et al. Low-velocity impact-
induced damage of continuous fibre-reinforced composite
laminates, part II. Verification and numerical investiga-
tion. Composite Part A 2002; 33: 10631072.
71. Chen JK and Sun CT. Dynamic large deflection response
of composite laminates subjected to impact. Compos
Struct 1985; 4: 5973.
72. Kelkar AD, Sankar J, Rajeev K, et al. Analysis of tensile
preloaded composites subjected to low-velocity impact
loads. In: 39th AIAA/ASME/ASCE/AHS/ASC struc-
tures, structural dynamics, and materials conference and
exhibit and AIAA/ASME/AHS adaptive structures 7
Forum, Long Beach, CA, 2023 April 1998, pp. 1978
1987.
73. Mitrevski T, Marshall IH, Thomson RS, et al. Low-
velocity impacts on preloaded GFRP specimens with
various impactor shapes. Compos Struct 2006; 76:
209217.
74. Whittingham B, Marshall IH, Mitrevski T, et al. The
response of composite structures with pre-stress subject
to low velocity impact damage. Compos Struct 2004; 66:
685698.
Agrawal et al. 331
at EKB-Public-Access PARENT on January 14, 2016jcm.sagepub.comDownloaded from
http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/http://jcm.sagepub.com/ -
7/25/2019 Impact damage on fibre-reinforced.pdf
16/16
75. Robb MD, Arnold WS and Marshall IH. The damage
tolerance of GRP laminates under biaxial prestress.
Compos Struct 1995; 32: 141149.
76. Karasek ML, Strait LH, Amateau MF, et al. Effect of
temperature and moisture on the impact behavior of
graphite/epoxy composites: part IIimpact damage.
J Compos Technol Res JCTR 1995; 171: 1116.
77. Bibo GA, Leicy D, Hogg PJ, et al. High temperaturedamage tolerance of carbon fibre-reinforced plastics. 1:
impact characteristics. Composites 1994; 25(6): 414424.
78. Parvatareddy H, Wang JZ, Dillard DA, et al.
Environmental aging of high performance polymeric
composite: effects on durability. Compos Sci Technol
1995; 53: 399409.
79. Hale JM, Gibson AG and Speake SD. Tensile strength
testing of GRP pipes at elevated temperatures in aggres-
sive offshore environments. J Compos Mater 1998;
32(10): 969986.
80. Li G, Pang SS, Helms JE, et al. Low velocity impact
response of GFRP laminates subjected to cycling mois-
ture. Polym Compos 2000; 21(5): 686695.81. Pang SS, Li G, Helms JE, et al. Influence of ultraviolet
radiation on the low velocity impact response of lami-
nated beams. Composite Part B 2001; 32(6): 521528.
82. Ibekwe SI, Mensah PF, Li G, et al. Impact and post
impact response of laminated beams at low temperatures.
Compos Struct 2007; 79: 1217.
83. Salehi-Khojin A, Bashirzadeh R, Mahinfalah M, et al.
The role of temperature on impact properties of
Kevlar/fibreglass composite laminates. Composites Part
B 2006; 37: 593602.
84. Levin K. Effect of low velocity impact on compression
strength of quasi-isotropic laminate. In: Proceedings of
American Society for Composites: first technical confer-
ence, Marriott Hotel, Dayton, OH, 79 October 1986,pp.313325. Lancaster, PA: Technomic Publishing
Company.
85. Zimmerman RS and Adams DF. Impact performance of
various fibre reinforced composites as a function of tem-
perature. In: Proceedings of 32nd International SAMPE
symposium, Anaheim, CA, 69 April 1987, pp.14611471.
86. Son KH and Kwon Young J. Effects of temperature on
impact damages in CFRP composite laminates.
Composites Part B 2001; 32: 669682.
87. Davies GAO, Zhang X, Zhou G, et al. Numerical mod-
eling of impact damage.Composites1994; 25(5): 342350.
88. Davies GAO and Zhang X. Impact damage prediction in
carbon composite structure.Int J Impact Eng1994; 16(1):
149170.
89. Zhang X. Impact damage in composite aircraft struc-
turesexperimental; testing and numerical simulation.
Proc IMechE Part G: J Aerospace Engineering 1998;
212: 245259.
90. Schoeppner GA and Abrate S. Delamination threshold
loads for low velocity impact on composite laminates.
Composites Part A 2000; 31: 903915.
91. Belingardi G and Vadori R. Low velocity impact tests of
laminate glass-fibre-epoxy matrix composite material
plates. Int J Impact Eng 2002; 27: 213229.
92. Matemilola SA and Stronge WJ. Low speed impact
damage infilament-wound CFRP composite pressure
vessels.J Pressure Vessel Technol1997; 119(4): 435443.
93. Alderson KL and Evans KE. Failure mechanisms
during the transverse loading of filament-wound pipesunder static and low velocity impact conditions.
Composites 1992; 23(3): 167173.
94. Hirai Y, Hamada H and Kim JK. Impact response of
woven glass fabric composites effect of fibre surface
treatment.Compos Sci Technol1998; 58(1): 91105.
95. Zhou G. The use of experimentally-determined impact
force as damage measure in impact damage resistance
and tolerance of composite structures. Compos Struct
1998; 42: 375382.
96. Cartie DDR and Irving PE. Effect of resin and fibre
properties on impact and compression after impact per-
formance of CFRP. Composites Part A 2002; 33:
483493.97. Sjoblom P. Simple design approach against low velocity
impact damage. In: Proceedings of 32nd SAMPE sym-
posium, Anaheim, CA, 69 April 1987, pp.529539.
98. Dorey G. Impact damage in compositesdevelopment,
consequences, and prevention. In:Proceedings of the 6th
international conference on composite materials and 2nd
European conference on composite materials, Imperial
College, London, UK, 1988, vol. 3, pp.3.13.26.
99. Aktas M, Atas C, Icten BM, et al. An experimental
investigation of the impact response of composite lamin-
ates. Compos Struct 2009; 87: 307313.
100. Atas C and Sayman O. An overall view on impact
response of woven fabric composite plates. Compos
Struct 2008; 82: 336345.101. Karakuzu R, Erbil E and Aktas M. Impact character-
ization of glass/epoxy composite plates: an experimental
and numerical study. Composites Part B 2010; 41:
388395.
102. Zaretsky E, Igra O, Zhuk AZ, et al. Deformation modes
in fibreglass under weak impact. J Reinf Plast Compos
1997; 16: 321331.
103. Tokheim RE, Erlich DC and Kobayshi T.
Characterization of spall in Kevlar/epoxy composite.
In: Schmidt SC, Johnson JN and Davison LW (eds)
Shock compression of condensed matter. Amsterdam:
Elsevier, 1989, pp.473476.
104. Dandekar DP, Boteler JM and Beaulieu PA. Elastic
constants and delamination strength of a glass-
fibre-reinforced polymer composite. Compos Sci
Technol1998; 58: 13971403.
105. Syam B, Homma H and Nakazato K. Fracture behav-
iors of GFRP plates subjected to impulsive loading.Key
Eng Mater 2000; 183187: 893898. In: Fracture and
strength of solids, Zurich-Uetikon: Trans Tech
Publications.
332 Journal of Composite Materials 48(3)