Accuracy and Response of Tourmaline Gages for Measurement of Underwater Explosion Phenomena.
Final rept. Jul 80-Jul 82,
NAVAL SURFACE WEAPONS CENTER SILVER SPRING MD
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Tourmaline gages have been used for some time to record and study underwater shock phenomena from explosions. Tourmaline is unique in that its piezoelectric constants are the same polarity. It does not require constraint in one dimension and thus, a diaphragm, as do many other types of transducers. Tourmaline gages are constructed by the Naval Surface Weapons Center from discs 18 inch to 2 inches in diameter, sandwiched up to four layers thick. The crystals must be waterproofed and protected. Coating materials generally alter the transducer response andor gage constant, sometimes in unpredictable ways. The response characteristics of silicone oil booted gages are compared to those predicted by mathematical derivation for a bare crystal gage. Tests and comparisons of actual gages of various size with various explosive types and charge sizes were made. The rise characteristics and accuracy of the real gages compared well with the derived predictions. Useful curves are given to predict accuracy in data measurements and to aid in the gage size selection for a given explosive charge size and range.
- Test Facilities, Equipment and Methods