Numerical investigations of microscopic characteristic influences on the mechanical properties of polymer-matrix composites

In this study, an isoparametric micro-mechanical model is developed to study the failure behaviors under biaxial loadings for composites with different fiber arrangements. For validating the method, the numerical results of the unidirectional (UD) composite lamina with consideration of two different failure criteria (the constituent failure criterion and UD failure criterion) are compared with the experimental results. On this basis, the fiber arrangements and fiber off-axis angles influence on the failure envelopes for the UD composite lamina are studied. Furthermore, the failure strength of a typical composite laminates is also investigated. The results show that the failure strength of composite laminates is closely dependent on the fiber arrangements. Compared with the hexagonal packing, the square diagonal packing provides the higher failure strengths. POLYM. COMPOS., 38:2734–2742, 2017.