On the formation of martensite in front of cracks in pseudoelastic shape memory alloys

In the present study we use finite element stress and strain analysis to study the stress induced martensitic transformations near the crack tip of compact tension (CT) specimens of pseudoelastic NiTi shape memory alloys. For this purpose, Aurichio's model for pseudoelasticity was implemented into the finite element code ABAQUS. The material parameters required in the model were adjusted according to loading/unloading data from pull-pull tests on pseudoelastic NiTi wires. Stress induced martensite forms near the notch of a CT specimen with no pre-crack. The presence of a sharp pre-crack alters the results considerably. The results presented in this paper provide some guidance for the interpretation of fracture mechanics tests on pseudoelastic shape memory alloys.