On the implementation of FEA for the design and development of a new biaxial tensile test fixture for uniaxial testing machine: a validation for cruciform test specimens

Sheet metals tend to have an anisotropic behavior due do their manufacturing process; hence, specialized equipment is needed for its mechanical characterization. In this work, the design for a biaxial tensile testing fixture, which can be used along with a universal testing machine for the characterization of sheet metals, is presented. First, a conceptual design of the fixture was generated, considering multiple characteristics observed on the devices existing in the literature; this conceptual design was evaluated using finite element analysis (FEA), and the results were validated with a prototype manufactured through additive manufacturing (AM). Based on the conceptual AM prototype, an iterative detailed design was carried out, in which FEA was used to estimate the performance of the fixture during test and dimensioning the different parts. Lastly, a fully functional prototype of the fixture was manufactured and tested with cruciform specimens fabricated from soft materials. The experimental results showed that the movements and performance of the fixture were adequate for the development of a biaxial tensile test. Thereby, the obtained results provide evidence of the advantages of using computer-aided design, FEA and AM synergistically, for the development of the proposed mechanism.