Distributed Piezoelectric Thin Film Sensor Array for Monitoring Impact Events

Accurate monitoring of impact events is of paramount importance for structural health monitoring, quality control and failure analysis of numerous structures. The present paper reports on the application aspect of distributed piezoelectric Thin Film Sensor Array (TFSA) for the impact force measurement. The distributed TFSA consists of 3x3 sensing element matrix of piezoelectric ZnO thin film. Highly c-axis oriented piezoelectric ZnO thin film was deposited on the flexible Phynox alloy substrate by RF reactive magnetron sputtering and was characterized by FESEM and AFM techniques. The individual sensing element is a MIM (Metal Insulator Metal) type structure. The ZnO thin film acts as an impact sensing layer and is sandwiched between Phynox common electrode and silver thin film as a top electrode. The overall dimension of the developed TFSA was 3cm x 3cm, and it monitors the location, force-time history and magnitude of the impact force. The developed piezoelectric TFSA has potential applications in monitoring the impact events on several composite structures like wings of an aircraft, crash testing of vehicles and wearable sports impact indicators.