On the influence of the shape of the interface law on the application of cohesive-zone models

The influence of the shape of the interface law on the analysis of debonding problems via cohesive-zone models is addressed. Four different laws have been considered whose shapes are bilinear, linear-parabolic, exponential and trapezoidal, respectively, and the input parameters have been chosen with a view to having the same values of the initial stiffness, of the maximum traction and of the associated fracture energy. In order to capture the main differences in the numerical responses of the four models, simple pure-mode problems have been analysed, three of them in mode I and one in mode II. Load–displacement curves and indicators of the algorithmic numerical performances are reported and discussed.