Evaluating the tensile deformation and stress of hyperelastic material based on transparent indentation method

A novel method is considered to evaluate the tensile deformation and stress of hyperelastic material by indentation method, the feasibility of which is on the basis of nonlinearity of hyperelastic materials. Under a tensile deformation, the instantaneous mechanical property shows an anisotropic character such that the contact region is elliptic rather than round. In order to capture the contact image, the traditional indentation device is upgraded with a special optical system. Besides, the spherical indentation experiment is conducted on the uniaxially stretched silica gel sample. The theoretical predictions and the experimental results show a good agreement with the difference from each other by less than 14%, that further validates the reliability of the transparent indentation method in spite of its insensitivity to the initial deformation. The aim of this paper is not only to evaluate the tensile deformation and stress of hyperelastic material but also to explore a new application domain of indentation method.