Modelling of shear failure caused by adiabatic shear banding and subsequent microvoiding
Résumé
An enlarged finite strain modelling is presented aiming at reproducing the loss of structural material resistance induced by the formation and growth of dynamic strain localisation bands known as adiabatic shear bands. In the modelling at stake, the adiabatic shear bands are embedded within the representative volume element and their kinematic and material effects are described using a specific velocity gradient and an anisotropic damage-like state variable, respectively. Criteria for adiabatic shear banding occurrence are discussed regarding the nature of the viscoplastic materials considered. At an advanced stage of deformation, micro-voids develop and grow within the adiabatic shear bands leading to the formation of micro-void sheets in the wake of the adiabatic shear bands. The kinematic consequences of this second softening mechanism – the first one being the adiabatic shear banding properly speaking - are accounted for by modifying the yield function/plastic potential within a unified large deformation modelling.