Analysis of the Planar-Biaxial Tensile Test Using Rakes: A Numerical-Experimental Approach

Abstract

The study of the mechanical behavior of materials through planar-biaxial tensile tests has been a relevant objective in recent years. While numerous authors have described different techniques and protocols for mechanical characterization using this method, there is no agreement on how to estimate parameters of a hyperelastic constitutive model through this test. In the context of small-scale samples, commonly some biological tissues, it is necessary to use a rake-type fixture. This fixture imposes a state of highly concentrated strains in the punch area of the sample, thus complicating the stress analysis of the material. In this study, the mechanical behavior of planar-biaxial tensile testing using rakes in an elastomer is analyzed, with a numerical-experimental approach that employs finite element method and contact analysis under high deformations. Finally, a strategy for optimizing mechanical parameters is proposed, considering the effect on stress concentration zones.