Wave propagation in the Taylor impact experiment

The high rate mechanical response of a hardened OFE copper was studied using the Taylor impact experiment. A high speed camera was used to record the deformation of the copper projectile. Analysis of the film images produced a position history of the plastic waves propagating in the copper rod material. From the position history data, wave speeds of the plastically deforming rod material were obtained.; To analyze the wave dynamics, the Mechanical Threshold Stress (MTS) constitutive relationship was used to describe the mechanical response of the copper. Material constants for the constitutive model were determined by a series of experiments under low strain rate and high strain rate conditions. The high rate mechanical properties were determined using a Split Hopkinson pressure bar.; Physical properties of the copper were studied using optical microscopy and x-ray diffraction. Texture in the material was determined at different strain levels following deformation under conditions of low strain rate and high strain rate. Results of this analysis showed a significantly higher level of grain rotation occurred under high strain rate deformation when compared at equal levels of strain.; The wave motion in the Taylor impact experiment was analyzed using the method of characteristics, a finite element analysis, and by the one-dimensional wave equations developed by Kolsky. The last of these uses the tangent modulus to the stress-strain curve to define a plastic wave speed. Each of these analyses were formulated to use the MTS description for the mechanical response of the copper projectile material.