Table 1.

Theoretical values of parameters m and ε, both of which are related to the contact geometry, for three axisymmetric tip shapes [38], where m is the power law exponent of Eq. (2) and ε is a factor used in determining the contact depth [see Eq. (6)].

Tip geometry	m	ε
Flat-ended cylindrical punch	1	1
Paraboloid of revolution	1.5	0.75
Cone	2	2 (π−2)/π