Rapid estimation of creep constitutive equation using digital image correlation and FEM

Abstract

Estimation of the creep constitutive equation requires uniaxial creep tests under various stress conditions, which is costly and time consuming. In this study, a rapid estimation method of a creep constitutive equation is investigated based on an inverse analysis using digital image correlation (DIC) and FEM. First, a steady-state creep strain field that develops non-uniformly near the stress raiser was measured by DIC. Next, an inverse analysis was performed to minimize the difference between the strain measured by DIC and the strain calculated by FEM, and the creep constitutive equation in the steady creep region was estimated. The strain rate calculated from the estimated creep constitutive equation were consistent with the results obtained from uniaxial creep tests at high stress side, though the strain rates were overestimated at lower stress condition, where the duration of transient creep is relatively longer.