A Guided Wave Sensor Enabling Simultaneous Wavenumber-Frequency Analysis for Both Lamb and Shear-Horizontal Waves

Abstract

Guided waves in plate-like structures have been widely investigated for structural health monitoring. Lamb waves and shear horizontal (SH) waves, two commonly used types of waves in plates, provide different benefits for the detection of various types of defects and material degradation. However, there are few sensors that can detect both Lamb and SH waves and also resolve their modal content, namely the wavenumber-frequency spectrum. A sensor that can detect both waves is desirable to take full advantage of both types of waves in order to improve sensitivity to different discontinuity geometries. We demonstrate that polyvinylidene difluoride (PVDF) film provides the basis for a multi-element array sensor that detects both Lamb and SH waves and also measures their modal content, i.e., the wavenumber-frequency spectrum.

Characterization of EMAT Guided Wave Reflectivity on Welded Structures for Use in Ranging

“…2DFFT is suitable for use with dispersive and non-dispersive modes [31]. This can be used to better extract information from multiple A-Scans by taking measurements in the spatial domain as well as the time domain allowing isolation of specific frequencies and their amplitudes [54]- [56]. 2DFFT is also used to validate the wave modes generated experimentally and in simulation [55], [57].…”

Application of ultrasonic guided waves to robotic occupancy grid mapping

“…SH waves oscillate perpendicular to the propagation path, and have particle motion in the transverse plane, while Lamb waves have particle vibrations in the sagittal plane [16]. The transverse polarization of SH wave modes may enhance the sensitivity of this type of guided wave to certain types of structural features such as welded regions, as well as the sensitivity to defects oriented parallel to the wave vector [32,33].…”

Modeling Magnetostrictive Transducers for Structural Health Monitoring: Ultrasonic Guided Wave Generation and Reception

“…Ultrasonic transducers for the generation and reception of guided waves in plates can be classified as either contact or noncontact. Contact transducers include piezoelectric angle beam transducers [ 1 ], piezoelectric wafer arrays [ 9 ], and piezoelectric fiber transducers [ 10 , 11 ]. For example, reference [ 11 ] developed a piezoelectric array that can simultaneously generate Lamb and SH waves using polyvinylidene difluoride (PVDF) film.…”

“…Contact transducers include piezoelectric angle beam transducers [ 1 ], piezoelectric wafer arrays [ 9 ], and piezoelectric fiber transducers [ 10 , 11 ]. For example, reference [ 11 ] developed a piezoelectric array that can simultaneously generate Lamb and SH waves using polyvinylidene difluoride (PVDF) film. Noncontact-type transducers include air-coupled transducers [ 12 , 13 ], electromagnetic acoustic transducers (EMATs) [ 14 , 15 , 16 , 17 , 18 ], and laser-ultrasound [ 19 , 20 ].…”