Singular plastic fields in wedge indentation of pressure sensitive solids

The paper examines singular plastic fields induced near the tip of a wedge indentating a pressure sensitive solid. Plane strain conditions are assumed and material response is modelled by the small strain Drucker-Prager rigid/plastic constitutive law. A standard separation of variables solution is numerically generated for pure power-law hardening. Three possible measures of wall roughness are studied with an attempt to expose the coupling between wall friction and material pressure sensitivity. Sample calculations illustrate that stress singularity decreases with increasing friction, wedge angle and hardening exponent, but increases with pressure sensitivity. At large values of the hardening exponent, when the material is nearly perfectly plastic, effective stress contours approach the slip line limit. The concept of indentation index is introduced as a possible estimate for average indentation pressure. (C) 2003 Elsevier Science Ltd. All rights reserved.