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Models for the behavior of solids submitted to shock waves include an equation of state and a plastic yield surface, which represents the plastic potential. The general purpose of this work concerns various methods used to obtain these equations by means of the determination of the mean and deviatoric shock streeses. Emphasis is placed on the method of ’’piezoresistive deviatoric gauges’’ that we have been using since 1973. This method does not include any theoretical hypothesis, and is suitable for all materials that can be gauged. Examples of applications on polymethyl metacrylate, limestone, and steel are reported and show that the precision of the piezoresistive deviatoric gauges method depends upon the material, namely the deviator magnitude, and upon the stress range explored.

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The shock loading and the unloading behavior of piezoresistive carbon gauges was investigated by means of impact experiments performed with a smooth bore gas gun. Experiments in the range 0.291–5.485 GPa provided shock stress-time profiles. Up to about 2 GPa the shock loading data were fitted with a least square polynomial in good agreement with other published date. Over 2 GPa the carbon presents a strongly scattering behavior. The unloading response in the reliable loading behavior range (0–2 GPa), exhibits an important hysteresis phenomena which could be imputed to the presence of pores in the carbon strip.