Physically-based modeling of cyclic softening and damage behaviors for a martensitic turbine rotor material at elevated temperature

A unified viscoplastic constitutive model coupled with a physically-based damage variable, is proposed to capture the cyclic mechanical behavior and microstructural evolution of the material at elevated temperature. The mechanical strength can be reduced by the decrease in the dislocation density, the coarsening of the martensitic lath and the loss of the martensitic structure under cyclic loading. The proposed physically-based damage variable is driven by the evolutions of dislocation density and martensitic lath width. The good com-parisons with test results mean that the proposed model can reasonably model the cyclic elastic-viscoplastic constitutive behavior of the material at high temperature.

Automated summary

The proposed unified viscoplastic constitutive model combined with a physically-based damage variable can effectively model the cyclic elastic-viscoplastic behavior of the material at high temperature, by considering factors such as dislocation density and martensitic lath width.