Identification of the constitutive equation by the indentation technique using plural indenters with different apex angles

This paper describes a novel technique for determining the constitutive equ ation of elastic-plastic materials by the indentation technique using plura l indenters with different apex angles. Finite element method (FEM) analyse s were carried out to evaluate the effects of yield stress, work hardening coefficient, work hardening exponent, and the apex angle of indenter on the load-depth curve obtained from the indentation test. As a result, the char acterized curves describing the relationship among the yield stress, work h ardening coefficient, and the work hardening exponent were established. Ide ntification of the constants of a constitutive equation was made on the bas is of the relationship between the characterized curves and the hardness gi ven by the load-depth curve. This technique was validated through experimen ts on Inconel 600 and aluminum alloy. The determined constitutive equation was applied to the FEM analyses to simulate the deformation including necki ng behavior under uniaxial tension. The analytical results are in good agre ement with experimental results.