Fracture behavior of PBX simulation subject to combined thermal and mechanical loads

Abstract

The fracture behavior and mechanical properties of a Polymer Bonded Explosives (PBX) simulation material were studied using the Digital Image Correlation (DIC) method. The fracture mechanism was analyzed as the material was subjected to combined thermal and mechanical loads. The macroscopic fracture mode changed from mainly shear action to a combination of extension and shear action, whereas the microscopic fracture changed from cleavage fracture and transcrystalline rupture to interfacial debonding, breaking of filler particles and a combination of transcrystalline and intercrystalline rupture. Micro-analysis of the creep properties showed the random nature of initial damage and the interaction between creep, damage and nearby damage, were the main reasons for the local creep strain repetition increase. During the process of high temperature creep, extensive cracks are first formed followed by the initiation and extension of shear cracks, eventually joining and causing a macroscopic fracture within the material. The main microscopic fracture mode has been found to be intercrystalline cracking and binder tearing failure.