Development of an Equibiaxial Tensile Test Device and Associated Test Method for Parameter Identification of Hyperelastic Ogden Model of Soft Material

Three different tensile tests are required to characterize a soft solid material that exhibits large deformations under external loading. The tensile tests include the uniaxial tensile, planar tensile, and equibiaxial tensile tests. In this study, a novel equibiaxial tensile test device was developed, and a test method combining the test device and a universal testing machine was proposed. Additionally, uniaxial tensile, planar tensile, and equibiaxial tensile tests of a silicone rubber were conducted, and stress-strain curves obtained from the three tests were then utilized to identify the parameter values of the hyperelastic Ogden model. The parameter values were validated by reconstructing the three tests in a finite element analysis software via the identified hyperelastic Ogden model. The findings indicated that the simulation results were in strong agreement with the test results. This validated the test method and the identified hyperelastic Ogden model. Furthermore, parameter values identified only by the uniaxial tensile test were used to perform the reconstruction analysis. The results of the analysis indicated that it was important to incorporate results from several types of tensile tests in the parameter identification process in order to obtain better simulation results.