Comparative analysis of two impact-sensitive sensors for improved estimation of time difference of arrivals

Abstract

In this study, an intensive comparative analysis of two impact-sensitive cantilever sensors for improved estimation of time difference of arrivals on plates is presented. Precise locating of the impact point requires exact bending wave propagation velocity due to the impact and time differences between each sensor. However since the bending wave velocity is dispersive on a plate, it is very difficult to decide the velocity when a vibration sensor such as an accelerometer is used. The new sensor philosophy is to provide a more exact bending wave velocity by designing the sensor as a cantilever type with a piezo transducer. Thus in this paper, two different cantilever sensors are considered: a rectangular type with a piezoelectric magnesium niobate — lead titanate single crystal patch and a circular type with a piezoelectric zirconate titanate disc. Their responses against impacts are compared with the response of a commercial accelerometer. The two sensors were manufactured and tested on a glass plate and an MDF plate separately. The impact test results showed that the two sensors give narrow band responses against impacts on the both plates and can provide a constant bending wave propagation velocity.