Bilinear approximations to the mode II delamination cohesive law using an inverse method

Cohesive zone modelling has proved to be a powerful tool to model delamination problems in high performance composites. Application to mode II delamination is of particular interest due to the large fracture process zone. In this paper, bilinear approximations to the mode II delamination cohesive law were determined for two carbon/epoxy composites. This was achieved by an inverse method that consisted of making Finite Element Analyses fit experimental load–displacement curves measured in well-known End-Notched Flexure tests. The optimal parameters of the bilinear cohesive law were determined by a genetic algorithm. The results showed the adequacy of the bilinear cohesive law and of the methodology employed.

► Mode II cohesive laws to deal with delamination growth in composites were achieved.
► The mode II bilinear cohesive laws were determined by an inverse method.
► The mode II bilinear cohesive laws were obtained for two carbon/epoxy materials.
► The optimal parameters of the cohesive laws were determined by a genetic algorithm.
► The results showed the adequacy of the cohesive laws and of the used methodology.