Temperature and strain rate dependent constitutive model of TRIP steels for low-temperature applications

The aim of this study was to develop a constitutive model that takes into consideration the strain rate and temperature dependent characteristics of TRIP steels, in conjunction with a damage mechanics approach. The martensitic-transformation-induced strain hardening of type 300 series austenitic stainless steels at low temperature is a remarkable phenomenon. From a mechanical point of view, the temperature and strain rate play critical roles in such material nonlinearities. A series of tensile tests for 304L ASS, which is representative of TRIP steels and cryogenic materials, were conducted at various temperatures and strain rates. The experimental results revealed nonlinear material characteristics of TRIP at low temperature and were simulated by the proposed numerical model. A strain-induced martensitic transformation model was implemented in a unified viscoplastic constitutive equation. The damage evolution equation was also incorporated into the proposed constitutive model to simulate material degradation. Using a series of finite element analyses, quantitative verification of the proposed numerical technique was carried out by comparing the experimental and numerical results.