Studies Of Bimaterial Interface And Its Mechanical Property With Peridynamics

Material interface fracture is the main failure mode of composite material component. As the fundamental research of the composite property, the research of bimaterial interface plays an important part in the performance evaluation of the composite. However, there are a series of problems in traditional bimaterial interface research with the theoretical, experiment and numerical methods.At present, the major numerical methods, based on the classical continuum mechanics, require complicated and special processing in dealing with the discontinuity. The peridynamic theory, proposed by Silling, formulate problems in terms of integro-differential equation rather than partial differential equations. In this manner, without the continuity approximation of the displacement field, it can describe continuous problems, fracture and particles in a unity framework.It needs special processing in dealing with the bimaterial interface with peridynamics. The tradition method, which translate the bimaterial interface problem from nonlocal to local theory, is complicated. This paper focused on the method of bimaterial interface handling with peridynamic theory and the related problems in bimaterial interface fracture research, more details is as follows:1. Based on the bond-based peridynamic theory, a weight function method has been proposed to describe the bimaterial interface bond model, and the series model and parallel model of interface bond has been established. The material parameter of interface has been determined, the validity of these two models has been evaluated, with the analysis of interface strain energy density and energy release rate.2. Existing coupled thermo-mechanical peridynamic theory has been improved by taking into account of the plastic work converted to heat. The correctness of the theory has been verified by comparing the numerical and experiment result of the crack propagation in a pre-notch single material model.3. In response to the mesh sensitive in solving crack propagation with peridynamics, a new perspective, neighborhood area and force vector distribution, has been proposed to analyze this problem. The appropriate horizon radius selecting method has been presented. It provides more accuracy without sacrificing the calculation efficiency.4. It’s necessary to refine the mesh at the bimaterial interface and crack tip. A leap-step mesh refinement strategy has been proposed. It distributes enriched particles over the original mesh locally without remeshing the whole domain. This method use the virtual node to satisfy the integrity of small elements’ neighborhood. In this way it can adapt to the crack tip move in dynamics analysis.