[溶接学会論文集 第 33 巻 第 ○ 号 p. 000s-000s（2015)]

Impact Analysis of Aluminum-Fiber Composite Lamina＊

by Yehia Abdel-Nasser**, Ninshu Ma***, Hidekazu Murakawa*** and Islam El-Malah**

Hybrid materials of fiber composite and aluminum alloys have a great potential in reducing the weight of transportation vehicles. It has been become an alternative solution to steel panels because they can provide high strength and improve energy absorbing capability under impact and collision loading. Developing a new composite material based on experiment by changing mechanical properties is quite expensive and takes long time. Therefore, numerical simulation with the aid of FEM is often performed, since its results have been proved to be close to the experimental ones. There are many different ways to combine the fiber into the resin. In this paper, the effect of lining arrangements of composite materials and the orientations of the layers on the strength was simulated using FEM in which the adhesive bond between fiber composite/metal is assumed as a tie constraint. Impact strength and failure modes of several plate panels with different lining arrangements were investigated. The results of analyses are presented and their trends are discussed.

Key Words: FEM, Hybrid Plate Panels, Lining Arrangements, Impact Analysis, Penetrations

1. Introduction

A composite material is fabricated by combining two or more

distinct materials together but remaining uniquely identifiable in

the mixture. The most common example is, a fiberglass

composite material, in which glass fibers are mixed with a

polymeric resin1). Composite materials are becoming increasingly

more attractive in a variety of structural engineering applications,

such as airplane fuselages, turbine blades, patrol boats and car

bodies. The challenge at hand is to use a composite material that

is optimized to provide the same or better strength and stiffness as

that of traditional isotropic materials. The amount of fracture load

at which a piece of fiber glass breaks, depends on the size of the

piece of fiberglass, its thickness, width, length, and also the

loading direction 2). It also depends on what the fiberglass is made

of such as layers orientations of fibers and amount of polymeric

resins. The goal of this paper is to analyse the strength of hull

structures made of composite materials as an alternative solution

to replace the heavy steel structure. It is anticipated that the use of

the composites will save on overall weight in order to maximize

potential payload capacity. The optimal composite design is

expected to be both lighter than the steel configuration, and

exhibited resistance to more severe loading conditions such as

impact loadings3). It is possible to design a composite material

such that it has the attributes desired for a specific application.

For example, fiber-Metal Laminates (FMLs) are a hybrid of metal

and composite laminates that are increasingly being used in

aerospace structures4). This is consisting of alternating layers of

thin metallic sheets and fiber-reinforced epoxy. Two main types

of FML are aramid fiber-reinforced epoxy /aluminum laminates

(ARALL) and S2 glass fiber-reinforced epoxy/aluminum

laminates (GLARE). The combination of mechanical properties

of monolithic metal and fiber-reinforced composite provides

FMLs with mechanical advantages such as low density, high

strength, and high damage tolerance. Impact damage is a key

concern for the safety of transportation vehicles5). Therefore it is

necessary to accurately predict internal impact damage to FMLs

and other composite materials6). Therefore, the goal of this

project is to rearrange lay-up of aluminum-fiber composite

lamina through changing mechanical properties and lining

arrangements of the layers, and comparing results of the

arrangements to obtain higher performance of the plate lamina

against impact and blast loadings. These changes can be virtually

done by numerical simulation using FEM-software such as

“ABAQUS”7). However, the numerical results required to be

verified through laboratory experiments.

2. Failure criteria

The failure of a composite panel will be resulted from either a critical strain or stress exceeded in the matrix or fiber. The composite behaves elastically and reaches to the point of failure, primarily because the glass fibers and the polymeric resin were both linear elastic solids with a brittle fracture mode, i.e., no

*Received: 2014.11.28 **Faculty of Engineering, Alexandria University ***Member, Joining and Welding Research Institute, Osaka

University

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plastic deformation. We would also note from the mechanical tests that the elastic modulus of the composite also varied with the amount of fiber added to the resin. Hashin’s failure criteria8) for Unidirectional Fiber Composites will be considered in this work. These are interacting failure criteria where more than one stress components have been used to evaluate the different failure modes. Usually Hashin criteria are implemented within two dimensional classical lamination approach for stress calculations with ply discounting as the material degradation model. After that, he extended the criteria to three dimensional problems where the maximum stress criteria are used for transverse normal stress component.

3. Description of FE models

The paper addresses the numerical simulation of impacts on

plate panels by applying FEM. The plate panels are composed

from hybrid material (S2 glass fiber-reinforced epoxy/ aluminum

laminates). The research work is aimed to optimize the

arrangement of composite layers which sustained the maximum

impact load. Other loads such as in-plane loads are not considered

here. The FE simulation of the impact analysis encompasses a

number of individual problems such as mesh size, element type

and time increments, which should be given appropriate attention

during the analysis. In the analysis, a fine mesh is generated

especially at the contact areas (mesh size=3x3x0.5mm) to acquire

accurate results and to represent real failure modes during impact.

Whereas coarse mesh may be applied for areas located far from

collision region to reduce CPU time. Also appropriate element

type (8 node break element) is selected to achieve accurately FE

analysis and increase the reliability of numerical models. The

adhesive bond between the glass/epoxy plies and aluminum

layers was modeled using the tie constraint module in Abaqus

software to express the delaminating failure. Abaqus/Explicit can

be applied to model nonlinear material behavior in a composite

laminate. Other problem such as modeling of the material damage

criteria is explained in Refs.9).

Abaqus/Explicit version is used to simulate the impact of plate

panels with a striking object such as ball or cylinder at different

velocity. The plate panels are modeled using solid elements

(C3D8R). The impactor (ball or cylinder) is modeled using rigid

elements (R3D4). This assumption is chosen because we are

interested in comparing the effect of the impact on the different

plate panels with no reference to the impactor. Different

configurations of lining arrangement are investigated. The

absorbed energy and contact force for each arrangement of the

plate panel are calculated after damage. The following

assumptions are considered in the models:

Volumetric ratio of composite (fiber/resin) is 50%.

The plies are symmetric laminated composites.

Unidirectional fiber or Random fiber is assumed.

Adhesive bond between Fiber/Metal is assumed as a tie

constraint.

4. Validation of FE models

Wu10) conducted a series of low velocity impact tests to evaluate the deformation and damage responses of FMLs. A comparative study is conducted using these experimental impact results to validate a basic numerical model. The model consists of two layers of Al 2024-T3 Aluminum alloy sheets and one layer of [0/90/90/0] S2 glass/epoxy composite. Here, Al is referred to the material of aluminum and /0/90/90/0/ is referred to 4plys of the composite material as shown in Fig.1. A steel spherical impactor of 12.3 mm diameter and with a mass of 6.29 kg impacted the plate panel with different impact energies such as 12.7J, 16.3J and 24.3J respectively. The hybrid plate panel (Aluminum-Fiber composite) of (0.076x0.076m) with total plate thickness 1.56mm is analyzed using FEM. The plate panel is clamped at all edges. The mechanical properties of S2 glass/epoxy4) are as shown in Table 1. The Aluminum 2024-T3 is assumed to be an elastic material and its characteristics are as follows: Young’s Modulus E= 73800 MPa and Poisson’s ratio ʋ=0.33. Hashin failure criteria are applied to trace the failure state of the composite material while the ductile failure criterion is applied for the aluminum. The tie constrained law is applied to express the adhesive bond between fiber composite and aluminum7). The time of impact is taken about 6 x10-3second.

Table 1 Mechanical properties of S2 glass/epoxy.

Material Parameter values (GPa)S2 glass/ epoxy

E11 E22 E33 G12 G23 V12 V23

55 9.5 9.5 5.5 3 0.33 0.33

Parameter values (MPa)

σLU,t σLU,c σTU,t σTU,c τLT u

2430 2000 50 160 50

The mesh model of the plate panel and the impactor are shown

in Fig.2. The impactor is moving with a constant velocity towards

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the plate panel. The numerical results show that the maximum

deformation is observed at the center of the plate panel. Figure 3

shows relationships between contact force and time for different

levels of energy. At low energy such as 12.7J the numerical

results have the same value in the contact force curve when

compared with the experimental results. However, for 16.3J and

22.3J energy, at the elastic state the same results are attained but

the deviations are observed after damage. Here, the numerical

results show higher contact forces than those attained by the

experimental ones. This is because the debonding of the

Aluminum layers and the composite layer was constrained using

the tied constraint. During the impact analysis of the plate panel,

failure modes such as plastic deformation of the metal layers

(Aluminum) and matrix cracking and fiber failure of the

composite layer are observed. Figure 4 shows relationship

between deflection at the center of the plate panel and the time.

The central deflection is reached to about 4.5mm and it is

increased as the impact energy increases. The effect of fiber

dimensions and orientations are not considered in this study11).

5. The impact behavior

In this section, the hybrid plate panel of 0.5x0.5m is modeled

with solid elements. The cylinder is modeled with 3D rigid

elements. The cylinder is moving towards the center of palate

panel with a high energy of about 2000J. The dynamic explicit

solver was used to account for the time-dependent loading and

the complex interaction between the cylinder and the composite

plate panel. The model with different arrangements of fiber glass

and Aluminum laminated layers are investigated to determine the

best arrangement that able to prevent cylinder penetration and

absorb the high energy (2000J). These model arrangements are

suggested as follows, (See Fig.5)

3GL (3 layers of Aluminum each layer has 4 mm thick and 2

layers of fiber glass/epoxy each layer has 3mm thick).

4GL (4 layers of Aluminum each layer has 3 mm thick and 3

layers of fiber glass/epoxy each layer has 2mm thick).

5GL (5 layers of Aluminum each layer has 2 mm thick and 4

layers of fiber glass/epoxy each layer has 2mm thick).

Each layer of the composite material is consisted of 4 plies

Fig. 1 The hybrid plate panel. Fig. 2 Mesh model of the hybrid plate panel.

Fig. 3 Relationships between the impact force and time. Fig. 4 Relationships between the deflection and time.

Rigid ball

Fiber layers

168s 研究論文　　YEHIA et al.: Impact Analysis of Aluminum-Fiber Composite Lamina

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with equal ply thickness and unidirectional of the stack sequences

(0/90/0/90). The local co-ordinate systems are defined to account

for orientations of individual plies and to model the laminate and

material behavior precisely. The material properties of the

composite are given in Table 1. While properties for Aluminum

are taken from Ref12). The cylinder of mass 8g and length 39 mm

impacts the center of the plate panel in the axial direction with a

constant velocity of 700m/s as shown in Table 213). Here, due to

the high energy, the time of impact is taken about 12x10-5 second.

Table 2 Characteristics properties of the cylinder 13).

Designation Weight g

Velocity m/s

EnergyJ

7.62x39mm 8 700 2000

The developed FE model is shown in Fig. 6. Fine mesh is

generated at the center of the plate panel.

Figure 7 shows the penetration of the cylinder into the plate

panel. It is noticed that for 3GL and 4GL arrangements, after the

plastic deformation spreads at the center of the face layer (Al) of

the plate, failure starts at the face layer (Al) then the cylinder

penetrates the face (Al) layer and reaches the composite layers

causing brittle damages in its plys. Finally, the cylinder penetrates

the second layer (Al) of the plate panel after causing large

deformation in this layer (Al). This process is repeated for

remaining layers of the plate panel. Figure 8 shows the ductile

fracture of aluminum layers and brittle fracture of the composite

layers. Figure 9 shows relationships between moving velocity of

the cylinder and time. At the beginning, the cylinder is moving

with a velocity of 700m/s, then its velocity gradually decreases.

For 3GL model, the cylinder penetrates the plate panel at time of

5.2x10-5 second and it still has a kinetic energy with a velocity of

about 138m/s. At the end a complete penetration is occurred.

Regarding 4GL model, the cylinder penetrates the plate panel at

time 6.1x10-5 second and its kinetic energy is gradually dissipated

with final zero velocity. For 5GL model, the cylinder could not

penetrate the plate panel. It approaches zero velocity and totally

lost its ballistic energy. It is noticed that with increasing number

of (Al) layers as in cases 4GL and 5GL arrangements; the

velocity of the cylinder is drastically decelerated. Table 3 shows a

comparative analysis for the previous arrangement using the

specified material properties.

In this analysis, the weight parameter defined by the weight per

area WP (kg/m2) of the plate panel is a little bit high. The weight

parameter WP (kg/m2) may be reduced by utilizing higher

strength of composite materials to get less plate thickness13). It

can be safely assumed that at high loading rates, as normally

observed in ballistics impact, the metal layers and glass fibers

undergo considerable hardening before failure thus providing

extended resistance.

Table 3 Characteristics of plate panel arrangements during

analysis.

Model Arrangement

Plate Thick(mm)

Time of penetration

(s)

Weight (kg /m2)

Failure of layers

End Velocity

(m/s)

3GL 18 5.2x10-5 44.4 All 138

4GL 18 6.1x10-5 44.4 Not All 0

5GL 18 Not 43 Not All 0

Fig. 6 Mesh model of the plate panel before and after penetration.

Fig. 7 Penetration of the cylinder into plate panel arrangements.

3GL 4GL

5GL Fig. 5 Different arrangements of hybrid plate panels.

Al Fiber

Penetration

Rigid Cylinder

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6. Conclusions

The paper refers to the simulation impact of

aluminum-fiber composite plate lamina using FEM which

provided close results compared with the experimental ones.

It is found that by increasing number of (Al) layers in the

lay-up arrangement of the hybrid plate lamina will

drastically decelerate the velocity of the impacted cylinder

and absorb higher impact energy (2000J). However, higher

weight parameter WP (43kg/m2) of the hybrid plate lamina is

attained. This may be reduced by utilizing higher strength

composite materials to get less plate thickness and weight.

Reference

1) D. Hull and T.W. Clyne: An Introduction to Composites Materials,

Cambridge University Press (1996). 2) D. Roylance: Introduction to Composite Materials", Department of

Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (2000).

3) C. Akin and M. Senel : An Expermental Study of Low Velocity Impact Response for Composite Laminated Plates, Dumlupinar University, Tr. (2010).

4) M. Rathnasabapathy, A.P. Mouritz and A.C. Orifici : Numerical Investigation of Fiber-Metal Laminates, 18TH International Conf. on Composite Materials Subject to Impact damage, (2008), Edinburgh, UK.

5) R. Kalavalapally, R. Penmetsa and R. Grandhi : Multidisciplinary optimization of a lightweight torpedo structure subjected to an underwater explosion, Finite Elements in Analysis and Design 43 (2006), 103-111.

6) S. Hyoungseock, J. Hundley, H.T. Hahn and J.Yang : Numerical Simulation of Glass-Fibre-Reinforced Aluminium Laminates with Diverse Impact Damage, AIAA Journal, Vol. 48, No. 3 (2010), pp 676-687.

7) Abaqus 6.10 2011: Damage and Failure Of Laminated Composite Plates , User manual Dassault System Rhode Island US.

8) Z. Hashin : Failure criteria for unidirectional fiber composites, Journal of Applied Mechanics Material Science and Technology, Vol. 47(1) (1980), pp 329–334.

9) P. CAMANHO AND C. ROSE : Failure Criteria for FRP Laminates, MS 240, NASA Langley Research Center Hampton, VA 23681, USA.

10) G. Wu :The Impact Properties and Damage Tolerance of Bidirectionally Reinforced Fibre Metal laminates, Journal of Material Science and Technology, Vol. 42, No. 3 (2005), pp 948–957.

11) P. Kumrungsie, K. Maneeratana and N. Chollacoop : Effects of Fiber Orientation on Ballistic Impact upon Polymer Composite Plate, The 21st Conference of Mechanical Engineering Network of Thailand 17-19 (October 2007), Chonburi, Thailand.

12) M. Luo, Ductile Fracture Characterization of an Aluminum Alloy Sheet using Numerical Simulations and Tests, Term Project Report of 2.094, MIT, (2008).

13) V. Phadnis, K. Pandya, N. Naik, A Roy and V. Silberschmidt : Ballistic impact behaviour of woven fabric composite: Finite element analysis and experiments, Journal of Physics: Conference Series 451, (2013).

Fig. 9 Relationships between the impact velocity and time.

(a) Ductile damages in Aluminum layers

(b) Brittle damages in composite layers

Fig. 8 Failure damages in the plate panel.

Aluminum

Fiber

170s 研究論文　　YEHIA et al.: Impact Analysis of Aluminum-Fiber Composite Lamina