Comparison of a New Sin-Hyperbolic Creep Damage Constitutive Model with the Classic Kachanov-Rabotnov Model Using Theoretical and Numerical Analysis

The creep deformation, damage, and life of creep susceptible components are a function of temperature, stress and strain rate. In this study the Kachanov-Rabotnov (KR) creep damage constitutive model and a recently developed Sinh creep damage constitutive model are compared in terms of accuracy, considerations/assumptions, constants evaluation techniques, flexibility in use, and limitations for 304 Stainless Steel (STS). Twenty tests performed at four different configurations of stress and temperature (five repeats for each) are collected from literature and used. It is found that the novel Sin-hyperbolic model exhibits lower constant dependency, is easier to apply, and more accurately models the creep deformations and damage evolution of 304 STS. The Sin-hyperbolic model produces a continuous damage (from zero to unity) by normalizing the experimental data while the KR model produces critical damage values well below unity. It is found that overall the new Sin-hyperbolic model offers more flexibility and prediction accuracy.