Gurson-Tvergraad-Needleman model-based damage analyses of stainless steel springs at high temperature

Abstract

In this paper, the Gurson-Tvergraad-Needleman (GTN) model is used to study the damage of stainless steel springs at high temperatures. The basic material and GTN damage parameters are determined from the stress-strain curves of tensile tests. Then the damage evolution of springs at 300 °C to 900 °C is analyzed based on finite element simulations. The results show that below 600 °C, the change of volume fraction of holes in the spring, along with the increase of load, has an obvious low growth stage, followed by a rapid growth stage. But above 600 °C, there is only a stable and rapid growth stage. The fracture positions predicted by finite element damage analyses agree with the experiments for round bars.