PIEZOCERAMIC SENSOR for MONITORING of STRUCTURAL VIBRATION
Since their discovery in 1880, piezoelectric devices have found widespread use in engineering applications due to their simplicity and ease of application. High on the list of applications is their versatility in sensor technology applications particularly as the key element in modern day accelerometers. Furthermore, recent advances in piezoelectric crystals have made them even more cost effective for use in low cost sensors for condition monitoring of structure. Traditional methods utilising acceleration and strain gauge signals for detecting an incipient failure in structures suffer from inherent difficulty due to massive damping characteristics of the structures which results in minute fault signals being buried in dominant background signal components. In this paper, common PZT materials such as PZT-5A and PZT-5H were used in the construction of piezoceramic (PZT) sensors. Experimental tests were performed to evaluate the performance of the PZT sensors in detecting a simulated bearing crack operating at low speeds (100 rpm) and comparisons made with a commercial accelerometer and an ultra-sound prob. The results show that the PZT sensor is a more sensitive device compared to a commercial sensors in detecting a minute crack of a rolling element bearing operating at low speeds. Work is in progress in using the PZT sensors for condition monitoring of bridge structures.