| Theodore von Kármán Professor of Aeronautics and Mechanical Engineering |
Research Interests Experimental Study of Adiabatic Shear Banding in Crystalline Metals Collaborator: G. Ravichandran, Caltech
|
In this work we use a high velocity air-gun to provide the asymmetric "shear" loading in prenotched metal plates. It has often been observed that low impact velocities (up to 100 m/s) result in the generation of dynamic cracks at the tip of the prenotch. If, however, the impact velocities are increased, the mode of failure switches from that of fracture to that of dynamic shear banding. This phenomenon of loading-rate dependent failure mode transition is not well understood. Here we use both optical and high speed infrared diagnostics to measure dynamically both deformation and temperature fields at incipient failure. The experiments are also modeled by extensive thermoviscoplastic finite element computations, which provide a benchmark for comparison with the experimental measurements. Materials to be tested include Ti alloys, C-300 steel as well as a variety of metallic glasses synthesized at Caltech.
last
update:
05/31/2016