Identification of model parameters from elastic/elasto-plastic spherical indentation

Abstract

Abstract Spherical indentation is commonly used to study the elastic and visco-elastic response of materials at different length scales. However, depending on the strength properties of the investigated material and the geometric properties, such as sphere radius and penetration depth, plastic material response might occur, making parameter identification from load – penetration curves a difficult task. In this paper, the influence of the aforementioned parameters is investigated by means of numerical simulations, considering elasto-plastic material response. The numerical results obtained are presented in dimensionless format, finally providing (i) general rules for the specification of test parameters in the case of spherical indentation, on the one hand, and – in the case plastic deformation takes place – (ii) relations for the determination of plastic model parameters (such as the deviatoric strength) from the loading phase of the indentation test.