BEM multiscale modelling involving micromechanical damage in fibrous composites

Composite laminates are materials where different scales are required for the understanding of the damage and for the calculation of structures made of these materials. The appearance of ultra thin plies of composites has opened the possibility of delaying the onset of damage, which at a first stage appears at a micromechanical level, debondings in between fibre and matrix in the weakest lamina of the laminate. A multiscale BEM model is developed in the present paper with the final purpose of being able to study the effect that the relative size of the laminas of the laminate plays in the appearance of this initial damage. The model presents many difficulties derived from the different scales involved in it and from the non-linear nature of the problem under study. The approach followed involves the solution of the whole problem, with the different scales involved in it, at once. The solution obtained is checked with another already obtained with a much simpler model. The multiscale model developed has been proved to be very efficient, accurate and robust, having been applied to simulate the first stages of damage in the light of the scale effect that is trying to be studied.