The elastoplastic constitutive model coupled with ductile damage based on micromorphic approach

Abstract : A thermodynamically-consistent micromorphic constitutive model fully coupled with ductile damage is formulated based on the generalized continuum mechanics. This model following the micromorphic approach proposed by Forest,introduces the new micromorphic damage and its first gradient to extend the local continuum damage model incorporating with the material characteristic length scale. Using the generalized principle of virtual work leads to the additional balance equations associated with micromorphic damage.The new damage energy release rate is derived from the extended Helmholtz free energy and regularized by the micromorphic damage. The micromorphic damage model as well as the classical displacements are implemented in finite element method. The numerical study of strain-softening and cracking in uniaxial tensile test and the cross-section drawing process of the DP1000 is performed. It is pointed out that the problem of mesh-dependency is avoided and the converged system responses are obtained and found to be consistent with experimental curves.