Coupled piezo-elastodynamic modeling of guided wave excitation and propagation in plates with applied prestresses

Plate-like aerospace engineering structures are prone to mechanical/residual preloads during flight operation. This article focuses on the quantitative characterization of applied prestress effects on the piezoelectrically-induced guided wave propagation, which has been widely used in structural health monitoring systems. An analytical model considering coupled piezo-elastodynamics is developed to study dynamic load transfer between a surface-bonded thin piezoelectric actuator and a prestressed plate. The accuracy of the analytical prediction is evaluated by the comparison with the finite element analysis. Based on the developed model, the load-dependent guided wave signal variation in both time-of-flight and amplitude is determined, and its dependence on loading frequency and host material properties is also discussed. It is found that the guided wave signal variation due to the prestress could be significant under some circumstances. A signal difference coefficient is finally proposed to quantitatively assess the signal variation caused by different prestresses. This study can serve as a theoretical foundation for the development of the real-time piezo-guided wave-based structural health monitoring system in a realistic loading environment.