Damage laws of cohesive zone model and selection of the parameters

The constitutive equation and the damage evolution of cohesive zone model were described in detail. The damage process of material under mixed-mode loading has been derived based on energy criterions, such as BK (Benzeggagh-Kenane) law, power law and others. It is noted that during the derivation of the damage process, the transverse stiffness and normal stiffness of the material are presumed to be independent. The way to determine the damage evolution law and its parameters through the MMB(mixed-mode bending) experiment is provided. In addition the multinomial law proposed shows good agreement with the experimental result.