Particle Reinforced Composite Interface Delamination And Matrix Crack Numerical Simulation

With the development of science and technology, composite materials, for their attractive behaviors, have been utilized more and more widely in many important industry fields, such as aerospace, automobile, military production, nuclear energy, electronic industry and so on. For particulate reinforced composites, the material properties, both mechanical and thermal, can be improved by the particulate inclusions., On the other hand, the strength of fracture and fatigue will be decreased at the same time. Both the positive and negative effects depend on the size, shape, properties, and spatial distribution of those second phase inclusions. Simulation of the behaviors of such composites, influenced by numerous microstructures, is one of the significant topics in the field of mechanics and material science.This dissertation deals with the two-dimensional simulation of particulate reinforced composites using an extended Voronoi Cell Finite Element Method (X-VCFEM). The main contributions can be listed as follows:1. Based on Voronoi Cell Finite Element Method(VCFEM), a scheme to describe the matrix-inclusion interfacial damage and the matrix crack propagation damage of particulate reinforced composites is proposed by establishing a functional, which is suitable to formulate all of the traction reciprocity conditions on the undebonded inclusion-matrix interfaces , the traction free conditions along the debonded interfaces and the traction free conditions along the matrix crack interfaces. Some improvement of VCFEM are proposed, such as, selection of appropriate stress functions and appropriate division of integral domains.2. A series of criteria based on the Mechanics of Interface and the Mechanics of Fracture are proposed for assessing the direction of damage development, which includes the matrix-inclusion crack branching along the debonded interfaces, the cohesive crack branching from the interface into matrix and matrix crack branching in matrix.3. A remeshing algorithm is proposed for the simulation of progressive matrix-inclusion debonding and matrix crack in particulate reinforced composites. The accuracy and efficiency of proposed methods are verified by comparison with the general nonlinear finite element codes MARC. At the same accuracy, the present methods have the advantage of mechanics computation of heterogeneous materials that element meshing is simpler and computation is faster for real particulate reinforced composites, in which multiple inclusions are randomly distributed.4. Using the X-VCFEM and considering the influence of the topological micro-structure of inclusions , the laws of matrix-inclusion debonding and matrix crack propagation in particulate reinforced composites was gained by establishing two ideal inclusions topology model.In present dissertation, with proposed methods, simulating the damage process of matrix-inclusion debonding and matrix crack propagation in particulate reinforced composites, the influence of the topological micro-structure of inclusions on the matrix-inclusion debonding and matrix crack propagation behavior have been analyzed.