A constitutive framework of plastically deformed damaged continuum and a formulation using the endochronic concept (Q1302792)

The authors discuss the concepts of continuum damage mechanics, and propose a constitutive framework of this mechanics for the description of infinitesimal deformations using the now classical notion of internal variables of state. Also classically, the framework involves the transformation of actual damaged continuum into an equivalent fictitious undamaged one. The authors use the notion of ``damage force'' (a thermodynamical force), of which the negative is related to the energy required to restore the fictitious undamaged continuum to its undamaged state after each step of deformation and damage. The coupling between the deformation and damage processes is provided by the damage restoring force concept. Within the proposed constitutive framework, the authors derive explicit constitutive equations by employing the endochronic concept (authors' theory adapted to K. C. Valanis' general introduction of endochronic concept). In an example, it is shown that the proposed model describes well the three-dimensional state of deformation of a cylindrical concrete specimen subjected to uniaxial compression.