Modelling of mixed damage on fibre reinforced composite laminates subjected to low velocity impact

This article presents a numerical technique for the computation of damage in fibre-reinforced laminated composites which is embedded into an explicit finite element method. The technique is composed of two main components. First, a novel characterisation of the directions in which the various modes of damage propagate, which produces an effective damage localisation. This is conducted taking into consideration the strain-rate dependence. Second, a new mapping between the strain and stress spaces for the computation of the damage surfaces whereby time-stepping convergence is enhanced. Additionally, new damage initiation criteria in terms of strain damage surfaces are presented. Details of the in-house code developed are presented as well as the programming features. The capabilities of the technique are shown by means of tests on single fibre-reinforced element and low velocity impact on the laminate. It is shown that delamination is located in the expected regions by gradual progression of internal damage variables.