Composite Piezoelectric Strip Transducer Development for Structural Health Monitoring

Piezoelectric fiber composite (PFC) transducers can be used to transmit and receive ultrasonic guided waves for structural health monitoring. Comb-type surface mounted PFC transducer strips are used to excite planar Lamb waves that interact with cracks and corrosion in a plate. Both finite element simulations and experiments examine the wave/defect interaction within a square domain that could be bounded by four strip transducers. In addition to transmitted, reflected, and scattered wave energy, beam spreading is investigated. Boundary conditions are applied in the finite element simulation to eliminate artificial end wall reflections. The experiments use a Doppler laser vibrometer to visualize wave propagation. Parallel PFC strips at wavelength spacing comprise an actuator that generates a wave field that is imaged by the scanning vibrometer. The results of the finite element simulation are qualitatively confirmed by the experiments.