A novel method to determine the electric, piezoelectric and elastic coefficients of fine scale piezoceramic fibers

A non-contacting, non-destructive method for the characterization of small signal properties on piezoelectric single fibers is presented. The technique comprises ultrasound generation, propagation and detection within the fiber. Two electromechanically active segments are prepared by applying two pairs of ring electrodes and subsequent poling of the interspace material. Measurements are carried out in pulse-echo-mode by transmitting and receiving ultrasound with one of the two poled segments. The other segment operates under either closed or open circuit conditions causing a small time difference during runtime measurement. Applying the piezoelectric equations, the electromechanical data k₃₃ and d₃₃ and the elastic compliance s₃₃ can be calculated. The practicability of the method was tested and verified for PZT fibers derived from the polysulphone process. The validity of the ultrasound runtime measurements is proved by simulation using an electromechanical model.