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Browsing by Author "Bo, Luyu"

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    Investigation of Viscoelastic Guided Wave Properties in Anisotropic Laminated Composites Using a Legendre Orthogonal Polynomials Expansion–Assisted Viscoelastodynamic Model
    Liu, Hongye; Huang, Ziqi; Yin, Zhuang; Sun, Maoxun; Bo, Luyu; Li, Teng; Tian, Zhenhua (MDPI, 2024-06-10)
    This study investigates viscoelastic guided wave properties (e.g., complex–wavenumber–, phase–velocity–, and attenuation–frequency relations) for multiple modes, including different orders of antisymmetric, symmetric, and shear horizontal modes in viscoelastic anisotropic laminated composites. To obtain those frequency–dependent relations, a guided wave characteristic equation is formulated based on a Legendre orthogonal polynomials expansion (LOPE)–assisted viscoelastodynamic model, which fuses the hysteretic viscoelastic model–based wave dynamics and the LOPE–based mode shape approximation. Then, the complex–wavenumber–frequency solutions are obtained by solving the characteristic equation using an improved root–finding algorithm, which leverages coefficient matrix determinant ratios and our proposed local tracking windows. To trace the solutions on the dispersion curves of different wave modes and avoid curve–tracing misalignment in regions with phase–velocity curve crossing, we presented a curve–tracing strategy considering wave attenuation. With the LOPE–assisted viscoelastodynamic model, the effects of material viscosity and fiber orientation on different guided wave modes are investigated for unidirectional carbon–fiber–reinforced composites. The results show that the viscosity in the hysteresis model mainly affects the frequency–dependent attenuation of viscoelastic guided waves, while the fiber orientation influences both the phase–velocity and attenuation curves. We expect the theoretical work in this study to facilitate the development of guided wave–based techniques for the NDT and SHM of viscoelastic anisotropic laminated composites.
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    Robot-assisted chirality-tunable acoustic vortex tweezers for contactless, multifunctional, 4-DOF object manipulation
    Li, Teng; Li, Jiali; Bo, Luyu; Bachman, Hunter; Fan, Bei; Cheng, Jiangtao; Tian, Zhenhua (American Association for the Advancement of Science, 2024-05-24)
    Robotic manipulation of small objects has shown great potential for engineering, biology, and chemistry research. However, existing robotic platforms have difficulty in achieving contactless, high-resolution, 4-degrees- of- freedom (4-DOF) manipulation of small objects, and noninvasive maneuvering of objects in regions shielded by tissue and bone barriers. Here, we present chirality-tunable acoustic vortex tweezers that can tune acoustic vortex chirality, transmit through biological barriers, trap single micro-to millimeter-sized objects, and control object rotation. Assisted by programmable robots, our acoustic systems further enable contactless, high-resolution translation of single objects. Our systems were demonstrated by tuning acoustic vortex chirality, controlling object rotation, and translating objects along arbitrary-shaped paths. Moreover, we used our systems to trap single objects in regions with tissue and skull barriers and translate an object inside a Y-shaped channel of a thick biomimetic phantom. In addition, we showed the function of ultrasound imaging–assisted acoustic manipulation by monitoring acoustic object manipulation via live ultrasound imaging.