Numerical Analysis of Low Velocity Rigid Body Impact Response of Composite Panels

This paper investigates various strategies to identify the most suitable approach for modelling the low velocity impact response of composite laminates. Three-dimensional meso-scale finite element (FE) models have been developed and implemented with user-defined material subroutines in ABAQUS. The models predict the simultaneous evolution of inter-laminar and intra-laminar damage mechanisms that occur in composite panels during impact. The effect of strain rate dependence on the damage response is taken into account, along with the effects of plasticity. Due to the extreme nonlinearities that occur, default values of control parameters in ABAQUS have been adjusted to obtain a converged solution. The paper describes the implementation of the various models and assesses their performance. The models use material characterisation information relating to M21E/34%/UD134/IMA carbon fibre reinforced polymer (CFRP). Experimental drop-weight impact tests, representative of low velocity rigid-body impacts, have been carried out in this work for model validation. Impact energy levels introduced by a rigid impactor were varied from 10 to 40 to evaluate the damage threshold and damage area that develops within the laminate. The results of the combined inter/intra-laminar model are in good agreement with experimental data, especially in terms of energy absorbed during impact. Numerical results provide an accurate description of the threshold at which a significant change in laminate stiffness occurs. It has been shown conclusively that an accurate delamination model is essential to correctly predict the impact response of composite laminates.