Modelling and Analysis of Rubberlike Materials

A numerical scheme for strictly and nearly incompressible rubberlike materials is described. A Total Lagrange description is adopted to describe the large deformations that occur. A separate interpolation for the displacements and the pressures is' used to model the (near) incompressibility. The employed constitutive model can be classified as hyperelastic with the strain energy function being composed of a deviatoric and a volumetric contribution. Thus, the volumetric deformations can be controlled in a physically realistic manner, which is important since experimental evidence indicates that, although the ratio of bulk modulus over shear modulus is very large for rubbers, volumetric strains cannot be neglected. The second part of the paper is devoted to a number of practical examples. It is shown that finite elements are very useful for assessing the strength and deformation characteristics of rubber components, but that a number of questions that are important for practical structures, are still open.Civil Engineering and Geoscience