Numerical investigation of nanoindentation size effect using micropolar theory

Abstract

In this work, we investigate the properties of micropolar continua in the conical indentation of elastic–plastic material. The micropolar formulation is derived in axisymmetric condition, and a finite element model is implemented for the elastic–plastic contact solution of the indentation problem. It has been shown that micropolar description of the material is consistent with the Nix–Gao indentation size effect model at high indentation depth. The size effects obtained from micropolar continua are governed by hardening rules and yield function rather than the material elasticity. The numerical simulations have been verified by the experimental results coming from the open literature. Moreover, it has been shown that the proposed micropolar model allows the prediction of indentation size effect for both micro- and nanoindentations at the same time.