ON THE INITIAL UNLOADING SLOPE IN INDENTATION OF ELASTIC-PLASTIC SOLIDS BY AN INDENTER WITH AN AXISYMMETRICAL SMOOTH PROFILE

A simple relationship between the initial unloading slope, the contact area, and the elastic modulus is derived for indentation in elastic-p lastic solids by an indenter with an arbitrary axisymmetric smooth pro file. Although the same expression was known to hold for elastic solid s, the new derivation shows that it is also true for elastic-plastic s olids with or without work hardening and residual stress. These result s should provide a sound basis for the use of the relationship for mec hanical property determination using indentation techniques. (C) 1997 American Institute of Physics.