A Continuum Damage Micromechanical-Based Model for Fracture Propagation in Viscoelastic Material

Resumo

The paper aims to model via micromechanics and macroscopic thermodynamic concepts a
propagation law for high densely fractured materials, formulated through a continuous damage variable that
account for incorporates the delayed viscoelastic material behavior. The first step of the approach is intended to
present the effective behavior of the viscoelastic fractured material and the damage activation criterion. The
Mori-Tanaka elastic homogenization scheme and the Laplace-Carson elastic/viscoelastic correspondence
principle are combined with an appropriate thermodynamic approach for formulating the damage propagation
criterion. This approach allows for analytical description of the macroscopic damage law, which can be handled
numerically in the time domain. Due to the damage variable evolution, it is necessary to formulate a non-linear
viscoelastic behavior law. The damage evolution rate is assessed by means of a reasoning inspired from
plasticity theory. The damage evolution algorithm relies upon the time integration of the damage evolution
through an incremental implicit scheme. The numerical implementation and application of the model emphasize
the time-dependent effects on damage propagation.