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The Lamb wave represents one of the most utilized forms of ultrasonic guided waves for flaw detection. A novel approach, to the best of our knowledge, for Lamb wave sensing using a fiber-optic quasi-distributed acoustic sensing (QDAS) system is proposed. Sensing elements constructed with optical weak reflectors are designed and analyzed, demonstrating the theoretical feasibility of establishing an ultrasonic sensing array comprising over 300 points. An empirical mode decomposition method is applied to this system to remove harmonic components in a frequency division multiplexed interrogation system. Verification experiments are carefully designed, employing compact 2.5 cm-sized sensing elements to capture 1 MHz Lamb wave signals on an aluminum plate. These findings significantly broaden the applicability of QDAS in the field of ultrasonic flaw detection.
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http://dx.doi.org/10.1364/OL.537687 | DOI Listing |
Ultrasonics
September 2025
Paderborn University, Paderborn, Germany.
This study investigates the phenomenon of mode repulsion in Lamb waves propagating through two coupled plates with an elastic interface. Using a spring-based coupling model and the Scaled Boundary Finite Element Method, the dispersion curves of the coupled system are analyzed under various interface conditions-weak coupling, sliding boundary, and perfect coupling. This research highlights how the mechanical stiffness of the interface influences the separation of modes and the emergence of repulsion regions.
View Article and Find Full Text PDFUltrasonics
August 2025
School of Electrical and Mechanical Engineering, The University of Adelaide, SA 5005, Australia.
This paper investigates a new method to evaluate dynamic stress in plate or shell-like components due to propagation of elastic waves. The proposed method is based on collinear mixing of the stress wave with a high frequency (probe) wave, which is excited in the ultrasonic frequency range. The wave interactions generate linear and nonlinear responses such as the changes of the group velocity of the probe wave and generation of higher-order harmonics, respectively.
View Article and Find Full Text PDFUltrasonics
August 2025
Department of Applied Mechanics, Indian Institute of Technology Delhi, New Delhi 110016, India. Electronic address:
The time-reversal method (TRM) for Lamb wave-based damage detection faces challenges due to amplitude dispersion, which prevents achieving a zero damage index (DI) for undamaged structures. Additionally, the healthy state DI varies with input excitation frequency, which complicates establishing a consistent DI threshold, and a high threshold diminishes its sensitivity to damage. This article proposes a novel technique that eliminates amplitude dispersion in the main mode of the reconstructed signal after the time-reversal process, enabling a near-zero DI threshold.
View Article and Find Full Text PDFArXiv
July 2025
Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA.
The mechanical properties of arterial walls are critical for maintaining vascular function under pulsatile pressure and are closely linked to the development of cardiovascular diseases. Despite advances in imaging and elastography, comprehensive characterization of the complex mechanical behavior of arterial tissues remains challenging. Here, we present a broadband guided-wave optical coherence elastography (OCE) technique, grounded in viscoelasto-acoustic theory, for quantifying the nonlinear viscoelastic, anisotropic, and layer-specific properties of arterial walls with high spatial and temporal resolution.
View Article and Find Full Text PDFSci Adv
August 2025
PSL University, ESPCI Paris, CNRS, Institut Langevin, Paris, France.
Transcranial ultrasound imaging is usually limited by skull-induced attenuation and high-order aberrations. By using contrast agents such as microbubbles in combination with ultrafast imaging, not only can the signal-to-noise ratio be improved, but super-resolution images down to the micrometer scale of the brain vessels can also be obtained. However, ultrasound localization microscopy (ULM) remains affected by wavefront distortions that limit the microbubble detection rate and hamper their localization.
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