Prediction of the failure locus of C/PEEK composites under transverse compression and longitudinal shear through computational micromechanics

The potential of computational micromechanics to predict the failure locus of a unidirectional C/PEEK composite subjected to transverse compression and longitudinal shear was established. Numerical simulations were compared with the experimental results of Vogler and Kyriakides [Vogler TJ, Kyriakides S. Inelastic behavior of an AS4/PEEK composite under combined transverse compression and shear. Part I: Experiments. Int J Plasticity 1999;15:783–806], which contain detailed information of the matrix and fiber properties as well as the failure micromechanisms during multiaxial loading. Analyses were based in the finite element analysis of a three-dimensional representative volume element of the lamina microstructure and included the main deformation and failure mechanisms observed experimentally, namely matrix shear yielding and interface decohesion. In addition, the numerical predictions of the failure locus for composites with strong and weak interfaces were compared with those obtained by current phenomenological failure models to establish the accuracy and range of validity of these criteria.