Identifying hardware parameters

Given the number of existing models and the diversity of their mathematical formulations, the choice for the engineer is difficult. In fact, for a given experimental uniaxial tensile curve, it is always possible to find a hyperelastic model that reproduces this curve. At first sight, this result seems satisfactory; however, two major questions arise. Firstly, is the resulting set of material parameters unique? And if not, is it the "best" one? Secondly, even if the uniaxial tensile curve is well reproduced, is this the case for more complex deformation modes, i.e. for deformation states encountered in industrial parts and therefore in finite element simulations?

In practice, these difficulties can be summed up by the question: what is a good hyperelastic model for a given problem? Several rules, derived from experience, can be stated:

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