Inelastic Deformation of Metals Under Dynamic Loading.

The research is a study of the plastic response of metals to the application of dynamic loads. The study can be divided conveniently into two parts a experiments on short specimens in which the state of stress is essentially homogeneous and b wave propagation investigations. A split-Hopkinson bar for bi-axial loading of short specimens torsion and compression at equivalent strain rates of about 400 or 500sec was developed. The influence of annealing temperature on strain rate effects in copper was studied. Experiments were performed on thin-walled tubes of alpha-titanium in which pre-torqued tubes are subjected to an axial imapct. The results of these experiments cannot be explained satisfactorily using a strain rate independent theory. It was found necessary to develop a strain rate dependent theory which then predicted the actual material behavior with good accuracy. Modified author abstract