Comparison of VCCT and cohesive element methods on prediction of delamination growth in laminated ENF specimens

In this paper, the applicability and performance of two well-known methods, i.e., Virtual Crack Closure Technique (VCCT) and Cohesive Zone Model (CZM) are assessed for prediction of mode II delamination growth in laminated composites. To this end, End Notch Flexure (ENF) specimen is modeled in the commercial finite element software, ABAQUS®, and strain energy release rate is calculated by VCCT and using cohesive elements. A bilinear behavior is assumed for tractionseparation of cohesive element used along the crack tip. Comparison of numerical results with available experimental ones showed that the VCCT method, in spite of simplicity, cannot predict the propagation behavior in unidirectional ENF specimen with fiber bridging very well, while the CZM results are more accurate and reliable. Also, VCCT method is more time-consuming and sensitive to element size at the crack tip than the CZM. Thus, the results of this research provide a guideline for engineers during the structural design.