Orthotropic damage coupled with localized crack reclosure processing. Part I: Constitutive laws

The original model proposed present many advantages for applications which require cracks opening and reclosure management. It is easy to implement in most of the finite element codes based on a displacement formulation. It uses only measurable input data, like elasticity coefficients, tensile and compressive strengths, fracture energies and strains at the peak of the uni-axial stress–strain experimental curves. It supplies the crack opening perpendicular to the localized cracks directly, which can be plotted on the mesh. The orthotropic damage formulation on which it is based allows crack energy dissipation to be realistically verified and consequently ensures the objectivity of the FEM analysis toward the mesh size. Unilateral behavior and hysteretic dissipation due to crack re-closing phenomena are also considered in this framework. The latter aspect not only realistically predicts behavior during cyclic loading but, overall, provides a thermodynamic free energy form that can be generalized to treat quasi-unilateral aspects in various brittle materials concerned by crack re-closure problems.