The relationship between hardness and cone angle of conical indenters was s
tudied using finite element analysis for elastic-plastic solids with work-h
ardening. Comparisons were made between the present simulation results, sli
p line theory, and experimental results. Tabor's concept of representative
strain based on indentation experiments in metals (The Hardness of Metals,
Oxford, 1951) was shown to be applicable to a wide range of materials. The
relative size of plastic zone with respect to the contact radius was found
to influence the variation of hardness with indenter cone angle. The method
proposed by Atkins and Tabor [J. Mech. Phys. Solids, 13, 149 (1965)] for c
onstructing stress-strain curves using representative strains was also exam
ined, and the conditions under which the method is valid were obtained.