On the Development of a Testing Device for Fracture Characterization under Mixed-Mode Loading Conditions

Abstract

Because there is no codified standard for a mixed-mode fracture test, this study, by summing up previous works and investigating their properties, attempts to provide the requirements for standardization of mixed-mode fracture testing. Utilizing the loading device proposed in the present paper can help avoid the drawbacks of the previous methods applied for testing fracture toughness under mixed-mode conditions. The proposed fixture has a perfect symmetry that provides pure in-plane circumstances, preventing undesired third-mode loading conditions and creating a uniform stress state. The three-dimensional finite element models of the Arcan fixture and the suggested loading device were used to obtain the correction factors for the first and second modes. The results were then compared to investigate the variations of the fracture parameters. Moreover, analysis of the dimensionless stress intensity factors (SIFs) obtained for the third mode at various angles of loading led to the conclusion that the unwanted third-mode loading conditions had a considerable contribution to the Arcan device and, as a result, influenced the values achieved for the first- and second-mode dimensionless SIFs.