Identification of Plastic Properties through Spherical Indentation

Indentation has become a promising tool to characterize the mechanical parameters of materials. In this work, herein, spherical indentations on elastic-perfectly plastic materials and strain-hardening materials are investigated through finite-element method (FEM) simulations. A new method to extract the yield strength and strain-hardening exponent from spherical indentation is proposed. The deviation of nominal contact pressure from Hertzian prediction is used as an indicator to determine the plastic parameters. The difference between Hertzian contact pressure and real contact pressure is also investigated for the estimation of contact radius during indentation process. Herein, a more convenient approach is provided in this analysis to directly determine the mechanical parameters of elastic-plastic materials from spherical indentation tests. Validation of this method is presented in the form of a comparison between analytical stress-strain relationships and corresponding curves obtained via iterative FEM simulations of the indentation process. No experimental data are involved in this validation.

Automated summary

This work investigates spherical indentations on elastic-perfectly plastic materials and strain-hardening materials using finite-element method (FEM) simulations. A new method is proposed to extract the yield strength and strain-hardening exponent directly from spherical indentation. The deviation of nominal contact pressure from Hertzian prediction is used to determine the plastic parameters, and the difference between Hertzian contact pressure and real contact pressure is investigated for contact radius estimation. The validation of this method shows good agreement between analytical stress-strain relationships and FEM simulations.