A Modified Cohesive Zone Model for Simulation of Delamination Behavior in Laminated Composites
Considering the promotion effect of interlaminar normal tensile stress and the inhibition effect of interlaminar normal compressive stress,two kinds of elimination initial criteria were proposed in this paper. Based on these two delamination initial criteria,a modified cohesive zone model(CZM) was established to simulate the delamination behavior in laminated composites. Numerical simulations of double cantilever beam(DCB),mixed-mode bending(MMB)and end notched flexure(ENF)tests were conducted. The results show that the proposed model can do a better job than common ones when it is used to predict laminates’ delamination under interlaminar compression stress. Moreover,a factor r,named cohesive strength coefficient,was defined in this paper on account of the difference between cohesive strength and interlaminar fracture strength. With changing factor r,it shows that a moderate variation of cohesive strength will not cause significant influences on global load-displacement responses.Besides,in order to obtain a good balance between prediction accuracy and computational efficiency,there shall be two or three numerical elements within the cohesive zone.