Micropolar formulation for regularization of material instabilities in scalar damage models
Lapo Gori, Samuel Silva Penna, Roque Luiz da Silva Pitangueira
CILAMCE 2017 – XXXVIII Ibero-Latin American Congress on Computational Methods in Engineering , Florianópolis , 2017
Resumo (em inglês)
Strain localization is an important issue in the numerical modelling of the physically non-linear behaviour of quasi-brittle materials. Scalar damage models, and the wider class of elastic-degrading models, commonly used for the representation of quasi-brittle media, may suffer for material instabilities due to their strain-softening behaviour. When analyzed numerically with the finite element method, a set of pathological phenomena may appear, hence affecting the quality of the simulations. The micropolar continuum formulation has been showed, in the past, to be a valid alternative for the mitigation of localization issues in elasto-plastic models and, recently, also in the case of scalar damage models. This papers aims to investigate the regularization properties of the micropolar theory when applied to a scalar damage model, and to evaluate the effects of the micropolar material parameters (the Cosserat’s shear modulus and the internal bending length) on the onset of material instabilities. Analytical investigations are performed, in order to evaluate the onset of material instabilities with a proper localization indicator. Numerical simulations with the finite element method are also provided, in order to show the regularization properties of the adopted formulation.