DEVELOPMENT AND TESTING OF A NEW COUPLING DEVICE FOR PERFORMING IN-PLANE BIAXIAL STRESS TESTS WITH CRUCIFORM SPECIMENS

Abstract

Biaxial tensile tests provide more reliable information regarding the analysis of damage initiation and failure mechanisms, when compared to uniaxial tensile tests, for the characterization of materials, such as anisotropic, hyperelastic and heterogeneous ones, as they approximate conditions more realistic, which will be subject in practice. One of the most referred approaches in the literature to form the test configuration is the development of devices to be coupled in uniaxial machines. Therefore, analyzing the current needs, for the constant improvement of the test, a new coupling device to carry out biaxial tensile tests in the plane with cruciform specimens, was proposed in this work. The design methodology used includes the informational, conceptual, preliminary, detailed, and manufacturing and testing design phases. The numerical-experimental model, Finite Element Method (FEM), was used for the stress analysis of the mechanism. In addition, a functional prototype, printed in 3D, was developed to obtain a full-scale model in order to facilitate the analysis of its functionality. The device allows carrying out tests with variations in the loading rates between the two drive axles, in addition to being able to generate a state of plane deformation in the center of the specimen. The mechanism presents a reduction of components and a simplification in the manufacture and construction, in comparison with those found in the literature that allow test configurations similar to those that will be presented in this work. Due to the innovative character of this coupling device, the project generated a patent deposit.