Adhesive nonlinearity analysis of longitudinal guided wave using circumference pasted piezoelectric array based nonlinear shear stress lag model

Abstract

The adhesive layer between an ultrasonic transducer and a circular tube can generate a nonlinear signal during guided wave excitation and reception, which is called adhesive nonlinearity (AN). It may override the damage-related signals and result in false detection if not adequately evaluated and mitigated. This study investigated the AN of the guided wave excitation model composed of a piezoelectric array in a circular tube structure. The classical shear stress lag model was extended to the circumference pasted piezoelectric array-based nonlinear shear stress lag model to investigate the coupling properties of the AN and to evaluate the AN by comparing it with other nonlinear factors within a circular tube structure. On this basis, the nonlinear shear stress was combined with the normal mode expansion to establish a frequency tuning model for the AN, which allowed the effect of the AN to be minimized by adjusting the half-wavelength of the guided wave to match the length of the actuator. Finite-element analyses and experiments validated the tuning characteristics of the AN mentioned above. This work was used to mitigate the effect of the AN on the nonlinear guided wave during thermal damage evaluation.