Table 3.

Expression of pyramidal Hertz models.

Model	Expression of Elastic Modulus E	Multiplier Factor	References
Sharp pyramidal tip	$\frac{2}{1.4906}\frac{(1-v^2)}{tan\alpha {\delta }^2}\mathrm{F}$	$\frac{2}{1.4906}=1.341$	Bilodeau, 1992
Sharp pyramidal (developed from Bilodeau, 1992)	$\frac{4}{3}\frac{(1-v^2)}{tan\alpha {\delta }^2}\mathrm{F}$	$\frac{4}{3}=1.333$	Alcaraz et al., 2003
Blunted pyramidal tip	$\sqrt{2}\frac{(1-v^2)}{tan\alpha {\delta }^2}\mathrm{F}$	$\sqrt{2}=1.414$	Rico et al., 2005