Hybrid empirical/analytical modeling of guided wave generation by circular piezoceramics

Classical piezoceramic transducer design methods in structural health monitoring based on guided wave propagation rely mostly on the use of the pin-force model, assuming that a piezoelectric actuator can be modelled as a constant shear stress applied at its circumference, whatever the frequency generated. However, the assumptions of this model are only valid for thin piezoelectric elements, weak coupling between the host structure and the transducer, and when the wavelength of the generated guided wave is above the size of the transducer. In order to overcome those limitations, this paper presents an axisymmetric analysis of guided wave generation by a circular piezoceramic, considering the complex shear and normal interfacial stress profiles between the transducer and the host structure. The excitation terms are estimated empirically using a best-fit model and a function derived from measured admittance. The validity of the approach is assessed numerically and experimentally, and the influence of piezoceramic thickness on guided wave generation is accurately modeled for frequencies below the second electro–mechanical resonance frequency. (paper)