A comparison among several recent criteria for the failure analysis of composites

The failure analysis composites remains a topic still open to discussion. Indeed, despite the of progress of the research, none of the available failure theories is still able to accurately predict the failure at all levels of analysis, for all the loading and boundary conditions, failure modes, lay-ups, relative thickness and constituent materials. The criteria suited for specific classes of applications and the range of variation of their predictions with the variation of the design parameters are still unknown. In this paper, a bibliographical review that collects the most recent failure theories of composites with continuous reinforcement fibers, the recent improvements to existing theories and their applications is presented, together with a numerical assessment of their accuracy. Various criteria are compared considering various lay-ups, constituent materials, loading configurations, relative thickness and boundary conditions for which experimental results are available for comparisons. The analysis is carried out by a recently developed mixed, solid element whose nodal d.o.f, are the three displacement and the three interlaminar stress components, because it provides more accurate predictions with respect to displacement-based elements with a reasonably fine in-plane and through-the-thickness discretization. In the regions where the failure analysis is carried out, the fiber and matrix phase-averaged stresses are is used. It appears that the criteria can be accurate in a particular and inaccurate in other cases. In certain cases, the generalized failure criteria can be as accurate like the physically based failure criteria; the opposite can occur in other cases. However a group of criteria was identified that could be used for reciprocal checks.