A new biaxial tension test fixture for uniaxial testing machine - A validation for hyperelastic behavior of rubber-like materials

A new mechanism for a biaxial tension test is developed for loading an in-plane specimen simultaneously in two principal directions. This mechanism can be adapted to any uniaxial tension test machine and thereby it reduces the cost of conducting tests on expensive machines. It provides a uniform state of equibiaxial tension necessary for procedure characterizing the biaxial loading of any material system and particularly for understanding the hyperelastic behavior law of rubber-like materials for large deformations. The mechanism can also be utilized for evaluating an interaction coefficient of anisotropic or orthotropic materials like reinforced composites that can help in characterizing and predicting failure behavior. As a sample case, the experimental results obtained by this new mechanism are validated with the existing models for two rubber-like materials undergoing hyperelasticity.