Viscoplastic damage model for austenitic stainless steel and its application to the crack propagation problem at cryogenic temperatures

Austenitic stainless steel, or the so-called transformation-induced plasticity steel, exhibits high nonlinearity when strain-induced martensitic transformation occurs at various strain rates and temperatures, especially at cryogenic temperatures and high strain rates. The strong hardening, which is caused by the strain-induced martensitic transformation, is an important property of austenitic stainless steel. In this work, a viscoplastic model that considers the martensitic phase transformation of austenitic stainless steel is introduced in order to identify nonlinear mechanics, including the strong hardening phenomenon. In addition, the well-known damage mechanics approach is also used to predict material fractures under arbitrary loads. In order to apply the developed viscoplastic model to failures at the structural level, the crack propagation characteristics of an austenitic stainless steel plate are also predicted on the basis of the ABAQUS user-defined subroutine UMAT. In order to demonstrate the feasibility of the model, the simulation results are compared with the uniaxial tensile and crack propagation test results for the austenitic stainless steel plate.