Investigation of fracture behaviour of a complex interface crack using a modified interaction energy integral method under thermal shock loading

Abstract

The fracture behavior of advanced materials with complex interfaces is a critical concern in material design and manufacture. In this article, a novel method is proposed to capture fracture parameters of a crack in multiphase materials with complex interfaces under thermal shock loading. With the help of the designed auxiliary fields, the interaction energy integral method (IEIM), which is complicated by both the complex interface structure and the thermal shock loading, is simplified, making it applicable to various types of multiphase materials and the thermal shock conditions. Using this method, the crack growth in the complex interface structure of advanced multiphase material under transient, thermal shock loading is investigated. The evolution of the complex thermal stress intensity factors (CTSIFs) of mixed-mode around the interface crack tip is presented during the process of thermal shock loading, and the corresponding influence caused by the complex interface is examined from multiple perspectives. First, the relationship between the transient values of each CTSIF and the corresponding crack length is established during the thermal shock process. Both K₁ and K₂ exhibit distinct changes when the crack reaches the interface, which intersects its propagation path in all three multiphase materials. Next, from the variation of the peak values of each CTSIF, a potential well and a sharp variation in the slope of K₂ are identified in the process of thermal shock, which are attributed to the presence of the complex interface structure. These founds suggest that specific interface types within the complex interface structure can influence the CTSIF of the interface crack under thermal shock. Additionally, the strain energy release rate is computed and analysed. Based on its variation, the process of the interface crack growth under thermal shock is classified into the unstable and the stable growth. Those findings, along with the proposed IEIM provide valuable insights for the design, evaluation, and engineering applications of complex thermal interfaces in advanced materials.