An analysis of piling-up or sinking-in behaviour of elastic–plastic materials under a sharp indentation

Abstract

Finite-element simulation has been carried out to investigate the piling-up or sinking-in behaviour of elastic–plastic strain-hardening materials under a sharp indentation. An empirical model is proposed to relate the contact area to the material parameter E/σ_y and the experimental parameter h _e/h _max. Materials with E/σ_y<89.07 in the limit of vanishing friction and E/σ_y<150.7 for a friction coefficient μ = 0.2 may show only sinking-in. Other materials may show either piling-up or sinking-in depending on the h _e/h _max ratio or strain-hardening exponent. There is no universal h _e/h _max ratio that can be used to predict the piling-up or sinking-in behaviour of materials. Rather, the critical h _e/h _max ratio or strain-hardening exponent for no piling-up or sinking-in is a function of E/σ_y. The piling-up or sinking-in behaviour of materials is found to be closely related to fully plastic deformation. The influence of friction on the amount of piling-up or sinking-in has also been considered in this study.

Acknowledgements

This research has been supported by The Brinell Centre—Inorganic Interfacial Engineering, which is funded by The Swedish Agency for Innovation Systems (VINNOVA) and the following industrial partners: AB Sandvik Coromant, Seco Tools AB, AB Sandvik Hard Materials and Erasteel Kloster AB.