Volume 2, 2009DYMAT 2009 - 9th International Conference on the Mechanical and Physical Behaviour of Materials under Dynamic Loading
|1303 - 1309
|15 September 2009
Flow and failure behaviour of materials at high strain ratesE. El-Magd
Aachen University, 52056 Aachen, Germany
Published online: 15 September 2009
Strain hardening functions based on microstructure mechanical models are presented, which allow an accurate description of the flow curve over a wide range of strain. The influence of strain rate on the flow stress is described by functions that account for a continuous transition form the mechanism of thermal activated glide to the viscous damping mechanism. Different failure criteria are considered for dynamic multi-axial loading. Plastic instability promotes the deformation localisation and may lead to adiabatic shear banding. The debonding and fracture coarse precipitates lead to the initiation of micro-voids and micro-cracks and cause a stress drop at relatively small strains. Ductile fracture starts usually by initiation, growth and coalescence of voids. In the case of dominance of shear stresses, shear fracture is considered as an additional failure criterion.
© EDP Sciences 2009