Numerical modelling and analytical analysis of Shore OO hardness tests on soft materials

Abstract

In this work, the indention process with a standard Shore OO indenter is investigated with both numerical modelling and analytical approaches. For thick samples, both Johnson's (1985) model for elastic half space and the Hayes' (1972) model based on finite thickness are evaluated. For thinner samples, the Hayes' (1972) model and FE models are comparatively used to investigate Shore OO hardness testing of finite thickness samples. In both cases, FE models of Shore OO hardness test with bonded sample conditions are developed to simulate the effect of sample thickness. A re-meshing program is developed to incorporate large deformation of soft materials to reach the required level of load for the Shore OO hardness. The data from numerical modelling and analytical solution is systematically compared for cases of thick and finite thickness samples. A chart correlating the stiffness and the Shore OO hardness is presented and its potential use and influencing factors are discussed.