Penetration resistance: a new approach to the energetics of indentations

This article deals with quantitative applications of the penetration resistance (k = FN/h3/2) of experimental indentation loading curves without fittings or simulations in terms of the various energetic contributions for an improved understanding. The total applied work upon indentation with pyramids, cones and also spheres is partitioned between the indentation and the long-range effects including friction in a constant 80/20 ratio for mathematical reasons and thus for all of the diverse materials and methods. Long-range effects such as molecular migrations, rosettes, shear-bands, pile-up, sink-in, and elastic stress are recalled. An easy integration of (higher) parabolas with known exponent is presented. The constant ratios of applied work, indentation work, and long-range work allow for separation of surface effect work, reliable calculations of adhesion energies, and phase transformation energies. Corrections of Sneddon/Love and of Johnson, Kendall, Roberts (JKR) derived equations are now required.