Analysis of Casting Materials under Thermal Fatigue

Abstract

High-temperature components, for example turbochargers, are often subject to complex thermal and mechanical loading paths. Non-uniform temperature distribution and constraints by neighboring components result in complex timely varying stress and strain states during operation. In this paper the inelastic behavior of a casting material Ni-resist D-5S in a wide stress, strain rate and temperature ranges is analyzed. The material model including a constitutive equation for the inelastic strain rate tensor, a non-linear kinematic hardening rule and a damage evolution equation is developed. To calibrate the model, experimental databases from creep and low cycle fatigue (LCF) tests are applied. For the verification of the model, simulations of the material behavior under uni-axial thermo-mechanical fatigue (TMF) loading conditions are performed. The results for the stress response and lifetime are compared with experimental data.