Characterization of a combined interfacial element for laminated composites

A new interfacial element composed of a zero thickness cohesive element and eight rigid elements was introduced. Such interfacial elements were placed at the interface of shell structures to model the initiation and growth of delamination along the interface. The translational and rotational nodal movements of the adjacent shell element contributed to the deformation of the cohesive element. The type of the interfacial element was of finite thickness and eight-nodes, each of them possessed five degrees of freedom for coping with the corresponding shell element node. The rigid elements transfered nodal displacements and forces of the shell elements to the zero-thickness cohesive element by which the interlaminar damages were exhibited. The mixed mode bending (MMB) and double cantilever beam (DCB) bending tests were simulated by the shell and proposed elements, and the results agree pretty well with the experiments. Comparing with the traditional model of solid elements connected by cohesive elements, shell elements coupled with the suggested interfacial elements are easier to be used for the sheet-like or laminated structures with internal interfaces. The latter allows larger element size in the cohesive zone, reducing the total model scale and enhancing the computational efficiency.