Optimal sensor placement strategy and sensor design for high quality system monitoring

This paper presents a systematic investigation of the effect of sensor placement on the measurement data quality and subsequently, on the effectiveness of machine system health monitoring. First, signal propagation process from the defect location to the sensor was analyzed. Numerical simulations using finite element modeling was then conducted to determine the signal strength at several representative sensor locations. The analytical and numerical results showed that placing sensors closer to the component being monitored resulted in higher signal-to-noise ratio, thus improving the data quality. Using meso-sized piezoceramic chips, the obtained results were then experimentally evaluated. Comparisons with a set of commercial vibration sensors verified the developed sensor placement strategy. The presented study quantitatively justified why placing sensors closer to the machine being monitored is of critical importance to ensuring high quality data, and confirmed that the customized shock wave sensing approach can achieve comparable result for vibration measurement, but with a much less space requirement.