A Mode-Switchable Guided Elastic Wave Transducer

Increasing the safety demands of various progressively complex structures (e.g., in aerospace, automotive engineering, and wind power technology) and the parallel goal of reducing inspection costs set new objectives in the field of ultrasonics and guided elastic wave measurements. The focus is to deliver applicable sensors attached permanently to a particular structure for on-demand inspections. Piezoelectric fiber patches (PFPs) are known as lightweight and structure-conforming transducers for guided elastic wave generation and detection. We propose a new PFP concept combining advantages of different previous designs. With the new approach, a user can switch between a Lamb wave and a shear horizontal wave excitation by partially changing the polarity of the transducer electrodes. After summarizing the existing PFP variants, the new concept is introduced and experimentally verified by a three-dimensional laser Doppler vibrometer visualization of excited waves. Moreover, the first prototype of the new PFP transducer is presented.