A theoretical investigation of sharp indentation testing of a nearly-brittle material, with some experimental results

Indentation of brittle materials by a cone results in the formation of medi an cracks. The size and shape of these is predicted by using a combination of the finite element method to model the elastic-plastic indentation, and the eigenstrain procedure to model the cracks initiated during loading, and extended by residual stresses during unloading. The size and shape of the resulting crack are deduced, and compared with those obtained experimentall y in glass coupons. The influence of a pre-existing residual stress on the resultant final crack shape is inferred and also compared with experiment. (C) 2000 Published by Elsevier Science Ltd.