Determination of Material Constants of Internal Time Theory of Plasticity and Creep for Fatigue Analysis and Creep-Fatigue Analysis

Recent computer hardware is greatly developed to make possible fatigue analysis and creep-fatigue analysis of structures, which takes much computational time in the past. The code and standard recommend the simplified method in the fatigue analysis and creep-fatigue analysis instead of the detailed inelastic finite element solutions. It is widely recognized that the employed constitutive model affects inelastic finite element solutions significantly. However, the inelastic finite element solutions can consider effects of geometry shape or boundary conditions easily compared to the simplified methods. The other advantage of the inelastic solutions can also assist the mechanism of inelastic deformations. Thus, the accurate inelastic finite element solution is still intense research subject in this area.. The present paper will study constitutive model and the determination method of the material constants for the fatigue analysis and creep-fatigue analysis in order to simulate inelastic behavior at saturated condition, which differs from those at the initial loading.