Tandem pressure measurements in a hostile environment

Thick disc quartz gages have long been accepted by the defense community for recording shock stress. A unique combination of characteristics, however, make the carbon stress gage suitable for many weapon test applications. Both carbon gages and quartz gages were calibrated with gas guns utilizing thin flyers. Experiments are described which compare the response of the two types of gages to a nonplaner stress pulse generated by the detonation of an explosive, silver acetylide-silver nitrate (SASN). It was concluded from 18 pairs of gages tested at three impulse levels that detonation of the explosive at no less than 100 points/cm2 would produce equal peak stress currents from the two types of gages within 25%. Impulse derived by integrating the pressure-time profile from the carbon gages mounted on quartz gages did not agree with ballistic pendulum impulse data, possibly because of early cracking of quartz beneath the carbon gage. However, similar integration of the pressure profile of carbon gages mounted on flat aluminum, extrapolated for long times along a theoretical curve, gave an impulse practically equal to the directly measured impulse