Advanced Transducers for Remote Sensing and Structural Health Monitoring

Abstract

This paper reports on the design and testing of a novel class of ultrasonic/guided wave transducers for structural health monitoring. The transducers are particularly suited for harsh environments and remote monitoring of complex structural components. The design methodology takes advantage of the Fourier representation of the transducer and allows for smart patterning of the transducer inner shape, resulting in enhanced performance and reduced complexity of the devices. The design enables continuous beam steering and directional sensing which are achieved through proper selection of the excitation frequency (actuation mode), or through the detection of the dominant harmonic components in recorded signals (sensing mode). The design consists in a spiral geometry in the wavenumber domain, and thus is denoted as Wavenumber-Spiral Frequency Steerable Transducer (WS-FSAT). WS-FSATs are examples of a next generation of acoustic transducers that can significantly improve the practicality of guided-wave based sensors for structural health monitoring through embedded sensors in hard-to-reach areas.