Simplified cohesive zone analysis of mixed-mode I-II delamination in composite beams

Abstract

A simplified Cohesive Zone Model (CZM) was developed for the analysis of mixed-mode I-II delamination in composite beams. The present model applies to unidirectional laminates with half-thickness delaminations. Besides its beam theory basis, the present CZM differs from the common formulation in the piecewise linear softening and in the definition of dissipated energy adopted. Moreover, the consistency condition needed to ensure accurate results is embedded in the model developed. In this paper the analysis focused on the Moment-Loaded Cantilever Beam (MLCB) specimen for which an exact J-integral based analytical solution exists. The present results agreed with the latter solution despite some features that have been recently reported to compromise the accuracy of CZM i. e. non-linearity of the whole softening process, local mode-mix variations along the cohesive zone and large cohesive zones.