Title: SODIUM AND STRONTIUM SHOCK PRESSURE TRANSDUCERS.

Domino-shaped ferroelectric ceramic pieces were stacked together and explosively shocked, with the direction of shock travel normal to the direction of ceramic polarization. A commercial grade of barium titanate ceramic was used. It was found that the current output from a ceramic element is proportional to the width of the element. The voltage output is proportional to the thickness and the pulse duration to the length of the element in the direction of shock travel. (J.R.D.)

It is well known that the length and diameter of the transmission lines between a pressure transducer and the pressure source can significantly affect the dynamic frequency response of the transducer. A new lumped parameter model has been developed to predict the time and frequency response of any number of different transducers connected in parallel in a manifold. While the model is simple to apply, it can provide quantitative information given the transducer and transmission line characteristic parameters. More importantly, the model can be used to evaluate the measured, in-situ response. this provides the natural frequency and the effective dampingmore » which can then be used to generate a frequency response curve. The model is also useful for designing a new pressure transmission system, which will have the required frequency response. The model was qualified by comparison to measurements of the step-function pressure response of a number of different transducers and test installations. With the aid of the model, the system resonant frequency and damping can be determined. Additional damping can be added if necessary to prevent ringing of the signal and to assure an accurate pressure measurement with a flat frequency response. For all of the experimental systems evaluated in this work, the response at the natural frequency was significantly underdamped and ringing was observed. This means that to perform accurate measurements damping needs to be added to the system. It was observed that the use of flexible pressure lines versus hard lines does increase the damping and may therefore be useful in certain situations. Equations were developed to permit sizing an orifice to be added to the system to provide the necessary damping.« less

A series of hydrogen:air combustion tests were performed at the Fully Instrumented Test Site (FITS), located at Sandia National Laboratories in Albuquerque, New Mexico, to evaluate the performance of three strain-gage-type pressure transducers in a combustion environment. The three types of gages were: Precise sensor models 111-1 and 141-1 and Kulite model XT-190. The evaluation was required since these three types of pressure transducers had been used in previous combustion test series at the FITS facility and the results were inconsistent. During this evaluation testing, Brunswick 1101 stainless steel felt metal was used to provide thermal protection for the transducermore » diaphragms. The objective of this work was to determine experimentally whether such shielding alters the dynamic pressure response of a transducer during a combustion experiment. Results of the sixty tests indicated that the three pressure transducers, when thermally shielded with felt metal, recorded peak combustion pressures that were generally within 5% of the statistical mean for each test.« less