The objective function (Bhatti, Practical optimization methods: with mathematica applications, Springer, New York, 2000 [1]; Brandt et al, Criteria and methods of structural optimization, Martinus Nijhoff Publishers, PWN - Polish Scientific Publishers, Dordrecht, Warszawa, 1986, [2]; Rao, Engineering optimization: theory and practice. Wiley, Hoboken, 2009, [3]) for fitting of the criterion to the measured data can be formulated in many ways, which lead to different results. The following three kinds of objective functions mathematical, physical, and geometrical can be considered (Altenbach et al, Plasticity of pressure-sensitive materials. Springer, Berlin, pp 49–152, 2014, [4]; Kolupaev et al, Strength hypothesis applied to hard foams Appl Mech Mater, 70, 99–104, 2011, [5]).