Vickers indentations in glass—II. Comparison of finite element analysis and experiments

Abstract

This paper presents a comparison of a three-dimensional finite element numerical analysis of Vickers indentation with an experimentally observed indentation load—depth ( P—h) relation on soda-lime glass. Several mechanical properties, such as yielding stress, strain hardening and elastic modulus, are then estimated from the analysis of the experimental P—h curve. This paper also compares the experimentally-measured residual stress field around a Vickers indentation at the surface of glass with an FEM numerical calculation. The FEM calculation uses Mises elastoplasticity to describe the residual stress state at the unloading. The comparison shows a very good agreement between the numerical calculation and the experimental results for the P—h relation, the Mises stress and the hydrostatic stress. The results further confirm that the residual stress field close to the indentation is a non-equal bi-axial stress field, which is not circular in shape but reflects the shape of the indentation impression. The formation of radial cracks also causes significant modification of the stress field. The FEM analysis shows that the P—h relation can provide much useful information on mechanical properties using the analysis developed here.