On the Ways to Numerically Implement the Two-Time-Scale Approach

The focus of this paper is to describe the numerical implementation of the constitutive equations for the high-temperature steel X20CrMoV12-1 in combination with the two-time-scale approach into a finite element-program in order to describe the inelastic material behavior. The material is mostly applied in power plant components which are known to be subjected to high mechanical and also thermal loading. Hence, the overall aim is to model its response to a cyclic loading profile which occurs in the majority of time during operating. To increase the numerical efficiency, the two-time-scale approach is applied to the Armstrong-Frederick type constitutive equation for the inelastic strain rate and the evolution equation of the backstress tensor. The model is then implemented using a radial return-mapping algorithm into the finite element software ABAQUS.