Prediction of the cohesive strength for simulating composite delamination by a micro-mechanical model based on random RVE

A three-dimensional micro-mechanical model based on the random RVE is developed to predict the cohesive strengths of all the three delamination modes in unidirectional laminates. The interface RVE with two layers of randomly distributed fibers is established to represent the cohesive layer. Two types of random microstructure corresponding to the square and hexagonal periodic packing are defined. Delamination is assumed to be induced by matrix yield and cracking. The extended linear Drucker?Prager yield criterion and a paraboloidal yield criterion are used to predict the crack initiation in the matrix and compared with the major principal stress criterion. The predicted results show that the cohesive strengths are largely dependent on the type of random microstructure and the random microstructure morphology described by the minimum inter -fiber dis-tance and the fiber alignment angle. Global sensitivity analysis based on a polynomial chaos expansion surro -gate model is done to quantify the influence of the geometrical parameters on the variance of the cohesive strengths. Moreover, the predicted cohesive strengths are found to be unequal.

Automated summary

A three-dimensional micro-mechanical model based on the random RVE is developed to predict the cohesive strengths of all three delamination modes in unidirectional laminates. The predicted results show that the cohesive strengths are largely dependent on the type and morphology of the random microstructure.