Data-driven estimation of plastic properties in work-hardening model combining power-law and linear hardening using instrumented indentation test

Abstract

Instrumented indentation testing is an efficient approach for measuring mechanical properties such as equivalent elastic modulus and hardness. Recently, the indentation-based approach has been extended to estimate the stress–strain curve corresponding to tensile or compression tests. However, estimation performance is decreased in high work-hardening alloys because of the limitation of the functional expressiveness in a simple power-law hardening model containing two material constants. Although a modified constitutive model can be employed to improve the expressiveness, additional experimental data are required to adequately determine these material constants. In this study, a method for determining the additional material constant in a modified work-hardening model combining power-law and linear hardening was proposed without additional experimental data, based on the two stress–plastic strain curves of the power-law and linear hardening models. Consequently, the material constants can be determined using an existing approach. In this study, a data-driven estimation approach using the response surfaces of the loading curvature of a load–depth curve and the pile-up height of an indentation impression is established. The proposed approach was applied to high-work-hardening steel for validation.

Keywords

• elastic-plastic material
• instrumented indentation test
• response surface
• material database
• finite element method