Application of contact technology based on the user-defined cohesive element in the strength analysis of composite fastened joint

In order to solve the convergence difficulties caused by contaction in the analysis of composite bolted joints, the user-defined cohesive element with special constitutive behavior was developed to model contaction. This element could only transfer the pressure, but not the tension. The user-defined cohesive element was placed between the two interfaces in order to transfer the contact pressure, so that it becomes a way to guarantee the relation of coordination between the deformation of the two interfaces. Meanwhile, a three-dimensional progressive damage model was developed to model composite laminates with a single bolted joint. The stiffness reduction associated with damage due to compressive loads was improved based on the method of the document. The contact technology based on the user-defined cohesive element and the improved method of the stiffness reduction were used to predict strength of the model. At last, experimental results concerning the bearing strength were obtained and compared with the predictions, from which a good agreement was observed.