Shock Testing of an Endevco 851lA-2OK Piezoresistive Pressure Transducer.

The Defense Special Weapons Agency DSWA and the Navy are funding a project concept to provide information about an airframe, which includes a rocket motor, to help them meet program range and lethality requirements. The airframe is based on the Army high capacity artillery projectile HICAP concept, and the rocket motor is being developed. As a part of a static burn test of the rocket motor, the chamber pressure was monitored to aid in performance evaluation. It is also desirable to obtain the same chamber pressure information during the early flight tests of the projectile. Thus, it was decided to telemeter the on-board pressure data to provide information about the rocket motor burn. An Endevco model 8511A-20k piezoresistive pressure transducer was chosen to measure the rocket chamber pressure. This report discusses a test procedure where the transducer was shocked with several thousand gs and then calibrated. A comparison of calibration values for both pre-shock and post-shock events is included. The main conclusion of the report is that the specific transducer that was tested incurred a sensitivity shift, so that the output pressure values after the post-shock event varied significantly from those of the pre-shock condition.