Electromagnetic velocity-transducer studies of plastic waves in aluminum bars

In this investigation, annealed aluminum rods were subjected to dynamic compressive impact loading of duration of the order of 560 μsec to study the propagation of longitudinal plastic waves, using an electromagnetic transducer to record particle velocities at four stations approximately three inches apart. Test results indicate that any given level of particle velocity propagates along the bar with a constant speed, not affected by the strain rate, within the range of strain rates encountered. Good agreement was found between the propagation speeds observed for different levels of velocity (averaged over all tests) and predictions of the von Kármán rate-independent plastic-wave-propagation theory based on a single dynamic stress-strain curve almost coinciding with the static curve.