An improved power law criterion for the delamination propagation with the effect of large-scale fiber bridging in composite multidirectional laminates

Large-scale fiber bridging can significantly enhance delamination resistance, which makes the use of traditional delamination propagation criterion failed to accurately evaluate the delamination behavior in multidirectional laminates. This paper proposed an improved power law criterion to take account for the effect of fiber bridging on the delamination behavior. The key of the improved criterion lies on the introducing of R-curves, which can typically be determined by the standard delamination tests. A numerical delamination model based on the available cohesive elements was established with implementation of the improved criterion. The efficacy of the improved criterion is validated by the simulation of mixed mode bending delamination tests. Numerical results in terms of load-displacement curves agreed well with the experiment ones. The improved criterion can accurately evaluate the mixed-mode delamination with the effect of fiber bridging in a cost and time effective way, is convenient for applications.