A fast and efficient numerical prediction of compression after impact (CAI) strength of composite laminates and structures

Abstract

Abstract In this paper, an equivalent damage model is proposed to quickly predict the compression after impact (CAI) strength of composite laminates and stiffened panels. Low-velocity impact (LVI) and CAI tests at various energy levels are carried out on laminates. Based on the measured impact damage sizes, the model simplifies the damage area into concentric circles with different stiffness and strength properties by adopting the soft inclusion method. Progressive failure analysis and virtual crack closure technique (VCCT) are used to simulate the intra-laminar and inter-laminar failure of impacted laminates under axial compression in commercial finite element software ABAQUS. The predicted failure modes and CAI strength of laminates are in good agreement with the experiment results from this paper and the literature at various impact energies, which proves the validity of the model. Whilst the numerical model achieves high computational efficiency, the effect of mass scaling on computational efficiency and accuracy is evaluated, which provides a reference for the parameter choice in engineering application. The model is further applied to predict the compressive failure load of the stiffened composite panel with skin bay impact damage as a practical application, showing this modelling approach is also suitable to composite structures.