Analysis of ASB assisted failure in a high strength steel under high loading rate
Résumé
In the present work, the engineering, high strength ARMOX500T steel was submitted to a Kalthoff and Winkler type impact test in view of evaluating its crack arrest capability under dynamic loading. From an impact velocity of the order of 150m/s, the crack propagation is seen to be preceded by adiabatic shear banding (ASB) leading to a premature plate failure. The whole chronology of the plate failure mechanisms (weak localization, strong localization in the form of ASB then cracking) was observed thanks to the use of an ultra-high speed camera. Further digital image analysis allows for establishing displacement fields describing the kinematics induced by both adiabatic shear banding and crack propagation, in the perspective of being implemented into an embedded band/crack based model in the context of dynamic plasticity and fracture.