Identification of Plastic Properties through Spherical Indentation

• Published in: Advanced engineering materials 2022-11, Vol.24 (11), p.n/a
• Main Authors: Ding, Yue, Yuan, Wei-Ke, Liang, Xuan-Ming, Wang, Gang-Feng, Niu, Xinrui
• Format: Article
• Language: English
• Subjects: elastic–plastic contact; indentation; strain hardening; yield strength
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.202200379

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. Herein, a novel approach is proposed to extract the hardening exponent and yield stress of metal materials based on instrumented spherical indentation. For the identification of plastic properties, the difference of mean contact pressure between actual plastic indentation and elastic Hertzian contact is calculated as an indicator, of which the explicit expression is presented.