Integrated Sensor Arrays based on PiezoPaintTM for SHM Applications

Recent progress in development of new functional materials that are flexible and can be processed at very low temperatures (below 100 °C) opens a new opportunity for applications, such as non-destructive evaluation (NDE), or structural health monitoring (SHM) by applying active materials directly on the structures made out of a variety of materials, e.g. metals (aluminium), plastics, and polymers, including CFRP (Carbon Fibre Reinforced Polymer). This paper presents sensor arrays based on a flexible piezoelectric material – PiezoPaintTM. The newly developed material exhibits relatively high sensitivity (d33 coefficient up to 45 pC/N), extremely low processing temperatures (< 120 °C), and high compliance in the cured state, enabling direct deposition of acoustic/vibration sensor arrays on structures to be monitored by means of screen- or pad- printing. The printed sensors have been applied for impact detection where four-element arrays and a fully integrated wiring system has been deposited directly on aluminium as well as CFRP plates. The presented results show very good performance in terms of sensitivity, flexibility of usage, and ultra-low weight, making PiezoPaintTM technology an attractive alternative for SHM particularly in aerospace applications.