Modeling and studies of fracture in functionally graded materials under thermal shock loading using peridynamics

Abstract

In this study, an extended ordinary state-based peridynamic (OSBPD) model was proposed and applied to study the thermal shock damage and fracture of functionally graded materials (FGM) and structures. A modified term including thermal expansion coefficient is introduced into the conventional peridynamic model for investigating the thermal deformation of materials, and an influence function reflecting the gradient change of material properties is introduced into the force vector state in peridynamic model. The model and algorithm are validated by analyzing the cracking of a plate quenching in water and comparing with experimental results and available literature data. Furthermore, the effects of gradient distribution of elastic modulus, thermal expansion coefficient and fracture toughness of FGM on thermal damage and crack propagation are investigated. Numerical results show that the proposed model can effectively describe the failure process of functionally gradient materials under thermal shock loading. The distribution of elastic modulus, coefficient of thermal expansion and fracture toughness in FGM have great influence on the initiation and propagation of cracks, and reasonable gradient change form of materials can improve the thermal resistance ability of the structure.