On the determination of residual stress and strain fields by sharp indentation testing. Part I: Theoretical and numerical analysis

Sharp indentation tests, presently represented by cone and Vickers indenter s, are analysed theoretically and numerically in order to explore how equi- biaxial residual stress and strain fields can be determined from the global properties, i.e. the size of the contact area between indenter and materia l and the hardness. given by such tests. It is shown that the residual stra in fields can be accurately correlated with the hardness value while residu al stresses are related to the size of the contact area. The latter feature is explained by the Fact that the size of the: contact area is sensitive t o elastic effects. The results are summarized in simple closed form relatio ns. well-suited to be used in an experimental situation, and the range of v alidity for the resulting formulae is discussed. The predictions are compar ed with corresponding results taken from the literature and good agreement is found. An experimental scheme for determination of residual fields by in dentation is also suggested. (C) 2001 Acta Materiala Inc. Published by. Els evier Science Ltd. All rights reserved.