IDENTIFICATION OF PARAMETERS OF HYPERELASTIC MODELS FROM BIAXIAL TENSION TESTS

Paper in proceedings (conference paper)

en

Relationships between stress and strain components are nonlinear isotropic for elastomers such as rubber and nonlinear anisotropic for soft tissues such as artery wall. Isotropic as well as orthotropic hyperelastic constitutive equations are used for describing these properties. The quantitative definition of hyperelasticity is that material behaviour is such that the stress component is the derivative of an elastic potential function (or strain energy density function) with respect to the corresponding strain component. For a credible identification of hyperelastic constitutive equations and their parameters, it is necessary to use appropriate types of experimental tests. Typical tests for isotropic hyperelastic materials are: volumetric test, equibiaxial tension test, uniaxial tension test and pure shear test (or some of their equivalent tests). Combinations of data from multiple tests will enhance the characterization of the hyperelastic behaviour of a material. This paper presents a structural design of the equipment for biaxial testing of soft tissues as well as rubber, an analysis of the test types necessary for a credible identification of constitutive relations and their parameters and a method allowing the identification of parameters of constitutive relations.

biaxial tension tests, strain energy density function, artery

2007-06-04

Plzeň

978-80-7043-552-6

Experimental Stress Analysis

121–122

11