A flexible P(VDF-TrFE) piezoelectric sensor array for orientation identification of impulse stress

To realize a piezoelectric sensor array for identifying the location of impact stress, the large-scale (200mm x 200 mm) poly(vinylidene-trifluoride) (P(VDF-TrFE) 75/25mol%) films with thickness range from 20 mu m to 80 mu m are prepared using traditional solution casting method, which exhibits the favorable ferroelectric and electromechanical properties. By using screen printing with silver paste electrode, an orthohexagonal-shaped sensor array containing 19 P(VDF-TrFE) units is obtained. Then the dependence of output voltage of piezoelectric signal on the thickness of film and enforced impulse stress is investigated where an impact force testing machine is employed to simulate the impact of a flying ping pong ball. This piezoelectric sensor exhibits a large signal response of 8.9 V under an impulse stress of 1.5 MPa at an impacting speed of 500 mm/min. After signal acquisition and processing, the output signal wave of main senor and adjacent unit can be clearly distinguished from each other, and this array shows a fast response speed of 2 ms, indicating that this sensor array has a prospect of application in intelligent table tennis racket and other impulse signal monitoring area.