Damage in laminated composites under low velocity impact

Abstract

Composite materials are widely used in aircraft, automotive, marine and railway applications and may be exposed to impact loads, particularly low velocity impact. As material properties of composites are sensitive to strain-rate effects, conducting finite element analysis (FEA) of the impact simulation by using static material properties would not predict their behaviour accurately. Thus, the aim of this study is to incorporate strain-rate dependent behaviour influence into anisotropic damage model (ADM) and implement it in FEA for impact simulation. The study begins with extracting material properties data for ADM from published experimental data. The mathematical equation established from the extracted material properties were then used to develop the strain-rate dependent ADM and coded using ABAQUS/VUSDFLD, commercial finite element software. The developed strain-rate dependent (SRD) ADM was validated using published tensile test data. Impact simulation was conducted using both the static ADM and strain-rate dependent ADM and the results from the simulations were compared with published three-point bending impact experimental data at impactor speeds of 2, 3, 4 and 5 m/s for both cross-ply and angle-ply laminate orientations. The impact simulation results show that the incorporation of strain-rate dependency in ADM improves the prediction of three-point bending impact simulation reaction force by reducing the mean error from 33% to 14% for cross-ply laminates and from 12% to 10% for angle-ply laminates. This strain-rate dependent ADM impact simulation could thus be implemented as a design tool for analysing the impact damage resistant of laminated composites under low velocity impact.