Production of continuous piezoelectric fibers for sensor/actuator applications

Recent piezoelectric research has focused on composite structures for large-area hydrophone arrays and multifunctional `smart' materials for sensing and actuating, The field has been limited by a lack of materials which can be fashioned into sensor/actuator plies and integrated into host composite structures. ACI's Viscous-Suspension-Spinning Process (VSSP) has been refined for the production of piezoelectric fibers for use in transducer, sensor/actuator, and structural control devices. This process utilizes a fugitive carrier (cellulose) to form PZT powder into useful green fiber. The effect of the starting powder dispersion and spinning conditions, such as cellulose dehydration and regeneration in the spin bath, on the final green fiber quality are discussed herein. Careful control of the dispersion and the spinning conditions produces continuous green fiber of sufficient handling strength to weave into plies or cut for use in `pick-and-place' lay-ups. These lay-ups are then fired and resin-impregnated for the production of composites suitable for hydrophone or transducer applications. Recent results have yielded composites (25 vol% PZT) with d₃₃ = 340, pC/N, K = 470, and g₃₃ = 100 mV·m/N.