Delamination of surface accretions with structural waves: Piezo-actuation and power requirements

Abstract

Unwanted accretions on structures, such as aircraft and wind turbine icing or deposits in pipes, are a common problem, which can pose a serious safety threat if not treated effectively and punctually. In this article we investigate the capability of piezo-excited structural waves to delaminate accreted material. The core of the concept is to utilise the stress distribution associated with waves propagating through the structure to detach unwanted build-up. We apply a wave-based technique for modelling piezoelectric excitation based on semi-analytical finite elements to calculate the shear stress at the interface between the host structure and the accretion generated by piezo-actuated waves. Our analyses include the effects of the actuator’s dynamics and allow for comparing different types of actuators, identifying the most effective frequency of excitation and formulating realistic power requirements. For the dual purposes of proof of concept and validation of the model, we present a demonstration experiment in which patches of accreted material are removed from a beam-like waveguide with emulated anechoic terminations using ultrasonic excitation.