Laminated composite structures subjected to compressive loading: A material and structural buckling analysis

In order to improve confidence in composite structures design, a better description of the failure of laminates is necessary. A recent international exercise has evidenced that the current approaches overestimate drastically the strength of composites under compressive loadings, even for quasi-isotropic laminates. In the present paper, a complete approach is developed in order to overcome this problem. Firstly, a material multiscale failure approach, which can predict the failure for different stacking sequences under a large loading range, is proposed. This model describes accurately the failure of laminates when the final rupture is only due to material aspects (ply failures without buckling). Secondly, a structural analysis, taking buckling into account, is performed in order to improve the predictive accuracy of the model under compressive loadings. A simple method is proposed to predict buckling loads and the post-buckling behaviour, even in the case of a highly non-linear material behaviour. Comparisons between modelling and experimental results show quite a good agreement.