The deviatoric response of polymethylmethacrylate to one-dimensional shock loading

Samples of polymethylmethacrylate have been deformed by one-dimensional shock waves during plate impact. Manganin stress gauges have been introduced into the samples in such orientation that renders them sensitive to the lateral component of stress during shock loading. In combination with known Hugoniot data, these results have been used to determine the variation of shear strength with increasing impact stress. It has been observed that over the measured stress range, shear strength increases with increasing longitudinal stress. Comparison with the work of others shows close agreement. We also 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. Finally, we observe no change in mechanical behavior at ∼2.0 GPa, where others have noticed large changes in thermal and electronic responses.