An 'extended' anisotropic damage model based on Young/Poisson decomposition

One of the open challenges in anisotropic damage modeling is formulating damaged elasticity approaching general orthotropy. In this paper, with reference to previous work by the same authors, an ‘extended’ constitutive formulation of isotropic and anisotropic damage is proposed, which is based on a Young’s modulus/Poisson’s ratio decomposition of the initial isotropic compliance. Orthotropic damage is described through a second-order tensor damage variable. Main focus is on the secant relations and on the dependence of the engineering elastic parameters with damage as a function of a scalar characteristic parameter defining the slope of linear constrained damage paths in the plane of logarithmic damage variables.