<p>The acoustic metamaterial generating a unique non-diffracting hybrid order longitudinal Bessel-beam, we call Hybrid Bessel Beams (HyBe), with pronounced resilience to the scattering&nbsp;is currently unknown. While electromagnetic and acoustic metamaterials are aimed to manipulate wave energy to achieve a specific feature, an acoustic metamaterial microstructure outperform to demonstrate non-diffracting Bessel Beam are aspiring topic in research. Newly proposed hybrid Bessel beams are different than the conventional cross-sectional Bessel-beams. In this article, we explain the physics of multifunctional ultrasonic capabilities of a bioinspired interlocking architecture of acoustic metamaterial. At first for the newly proposed meta-structure, understanding the physics, wave energy is predictively focused through attenuative surfaces at various ultrasonic frequencies (~120 kHz to ~130 kHz). Finally, a zero-order first kind ultrasonic Bessel-like beam between frequencies ~265 kHz to ~272 kHz is shown propagating a long distance through the base material. The new propagation had minimal reduction in energy amplitude, while the displacement was nearly constant across the depth of the wave guide following a second order Bessel function of the first kind. To explain the physics of the phenomena, mode shapes in the frequency-wavenumber domain are investigated. Further, identification of propagating wave vector using equifrequency contour at multiple ranges confirmed the presence of the proposed acoustic features. These abilities of the proposed metamaterial have the key advantages to propagate wave deeper into the thick attenuative and aberrative structures such as brain tissue, soft skin and muscles, paint surface, non-accessible composite materials etc. We envision potential application of the proposed HyBe for the non-destructive evaluation of attenuative materials that are not easily accessible for testing. To verify the wave focusing and long-distance wave propagation, an ad-hoc metamaterial lens for conventional NDE transducer is proposed, which demonstrated wave propagation through a 10 mm thick carbon fiber reinforced polymer composite structure.</p>

Hybrid Bessel Beam and Metamaterial Lenses for Deep Laparoscopic Nondestructive Evaluation

Paper Proceedings: https://asmedigitalcollection.asme.org/qnde/QNDE2021/volume/85529

ASME 2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE2021)

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