Lamb wave propagation in anisotropic multilayered piezoelectric laminates made of PVDF-θ° with initial stresses

In this paper, the influence of an initial stresses on the Lamb waves propagation in an anisotropic multilayered piezoelectric laminates is investigated. Formulations are given for only open circuit surface; while the Legendre polynomial method is employed for calculate the wave propagating characteristics. To validate our numerical strategy, this polynomial approach was applied to simulate lamina composite structures. Relatively good results were obtained compared to reliable data available from the literature ones, with relatively significant computation effort. Convergence of the present method is discussed. Influence of initial stresses and fiber orientation angle on the behaviors of Lamb waves is analyzed. Results confirm that the behavior of Lamb modes depends not only on the initial stress but also on fiber orientation. Next, the dispersion curves of fundamental Lamb modes in sandwich plates with 0 degrees/theta degrees/0 configuration are calculated. Finally, the optimal angles in PVDF-theta degrees with initial stresses for which the Lamb modes exist are also analyzed. These results for the composite structures may render as a useful reference for the design of ultrasonic transducers in industry for non-destructive testing especially that encounters initial stresses.