Nonlinear elasticity for modeling fracture of isotropic brittle solids

A softening hyperelastic continuum model is proposed for analysis of brittle fracture. Isotropic material is characterized by two standard parameters-shear and bulk modulus-and an additional parameter of the volumetric separation work. The model can be considered as a volumetric generalization of the concept of the cohesive surface. The meaning of the proposed constitutive equations is clarified by the examples of simple shear and hydrostatic pressure. It is emphasized that the proposed constitutive model includes only smooth functions and the necessary computational techniques are those of nonlinear elasticity.