The deviatoric response of polymethylmethacrylate to one-dimensional shockloading

Samples of polymethylmethacrylate have been deformed by one-dimensional sho ck waves during plate impact. Manganin stress gauges have been introduced i nto the samples in such orientation that renders them sensitive to the late ral component of stress during shock loading. In combination with known Hug oniot data, these results have been used to determine the variation of shea r strength with increasing impact stress. It has been observed that over th e measured stress range, shear strength increases with increasing longitudi nal stress. Comparison with the work of others shows close agreement. We al so note that there is a small yet significant reduction in lateral stress, and hence an increase in shear strength behind the shock front. We believe this to be a manifestation of the viscoplastic response of this material. F inally, we observe no change in mechanical behavior at similar to2.0 GPa, w here others have noticed large changes in thermal and electronic responses. (C) 2000 American Institute of Physics. [S0021-8979(00)08624-2].