Piezo-resistive vibration sensor using liquid

Abstract

This paper reports on a piezo-resistive vibration sensor, which is liquid-beam-air multilayer structure. It is known that the similar structure sensor can detect acoustic emission, using surface tension wave, in the past research. In this paper, the behavior is clarified by performing two experiments. One is measuring the relationship between the liquid amount, which is liquid height, and the fractional resistance change per acceleration. The other is observing the actual vibration shape by use of laser Doppler measurement system. The result suggests that inertial force is dominant under about 20 kHz and the sensitivity is depended on liquid height. Above about 20 kHz, surface tension wave is dominant.