Numerical modelling of impact damage in fibre-reinforced plastic composites with smoothed particle hydrodynamics

This study develops a computational simulation method to predict nonlinearity, progressive failure behavior and failure strength of CFRP laminates using the SPH method. The fracture mechanism of CFRP laminate subjected to crushing may be categorized in four major failure modes, fiber tensile failure, fiber compressive kinking, matrix cracking and delamination. Hence, these failure modes are modeled in this study. In previous studies, the stiffness or stress values of damaged particles becomes zero instantaneously when the damage occurs. But, this may cause the unrealistic localization of damage. In order to overcome this problem, softening models are implemented in this simulation. The dissipated energy with fiber failure is exceedingly larger than with matrix damage. Therefore, one of the energy based damage model, called smeared crack model (SCM) was used to treat adequately the dissipated damage during fiber kinking. Additionally, in crushing phenomena, countless matrix cracks are generated and it is difficult to simulate individual cracks respectively. Hence, continuum damage mechanics (CDM) is used for modeling multiple cracks that are difficult to discretize in mesoscopic scale. For the modeling of delamination, the damage model considering the separation of interactions between particles is used to reproduce the separation of adjacent plies. In addition, it is known that CFRP shows different elasto-plastic response depending on the loading direction due to the pressure-dependence of epoxy resin. To reproduce this nonlinearity, an anisotropic pressure-dependent elasto-plastic material model is applied for conventional SPH.