This short note shows that contact stiffness under a non-Hertzian pressure distribution is 33% higher than that under a Hertzian pressure distribution. This is due to the fact that there is no physical indenter that gives a non-Hertzian pressure distribution during elastic contact, and the fundamental relation used in nanoindentation data analysis does not apply.
BorodichF. M.KeerL. M., ‘Contact problems and depth-sensing nanoindentation for frictionless and frictional boundary conditions’, Int. J. Solids Strut., 41 (2004), 2479–2499.
3.
FuG.CaoL., ‘On the fundamental relations used in the analysis of nanoindentation data’, Mater. Lett., 62 (2008), 3063–3065.
4.
PharrG. M.BolshakovA., ‘A understanding nanoindentation unloading curves’, J. Mater. Res., 17 (2002), 2660–2671.
5.
SchwarzerN., ‘Analysing nanoindentation unloading curves using pharr's concept of the effective indenter shape’, Thin Solid Films, 494 (2006), 168–172.
6.
HerrmannM.RichterF., ‘Determination of young's modulus of thin films using the concept of the effective indenter’, Phil. Mag., 91 (2010), 1356–1369.
7.
MerleB.MaierV.GokenM.DurstK., ‘Experimental determination of the effective indenter shape and ɛ-factor for nanoindentation by continuously measuring the unloading stiffness’, J. Mater. Res., 27 (2012), 214–221.
8.
JohnsonK. L., Contact Mechanics, (Cambridge University Press1985), pp. 107–108.
9.
TimoshenkoS.GoodierJ. N., Theory of Elasticity, (McGraw-Hill1951), pp. 366–377.
