Determination of creep parameters of materials using a stress relaxation method

The stress relaxation processes of prestressed cylindrical specimens were simulated by FEM. Assuming the creep of material obeys the Norton creep law: ε̇=Bσⁿ(ε̇ is the creep strain rate, B is a material and temperature dependent constant, and σ is the applied stress), we proposed two approaches to determine the creep stress exponent using the stress relaxation method. The first method requires a single stress relaxation curve. The second requires extracting the initial stress relaxation rate by an extrapolation method, and multiple stress relaxation curves are needed to yield the creep stress exponent. The present work provides some new notions on the determination of creep properties of materials which usually serve at high temperature.