Article
Engineering, Mechanical
Sergey Kuznetsov
Summary: The analytical and geometrical conditions for the possible appearance of infinite group velocity (IGV) points belonging to the dispersion curves of Lamb waves propagating in traction-free plates are studied. The study utilizes a combined method comprising Cauchy sextic formalism and the exponential fundamental matrix method. The obtained geometrical condition states that the IGV corresponds to the coincidence of a tangent line to any of the dispersion curves with a straight line passing through the origin.
JOURNAL OF SANDWICH STRUCTURES & MATERIALS
(2023)
Article
Engineering, Mechanical
Shuanglin Guo, Marc Rebillat, Nazih Mechbal
Summary: This paper explores the properties of dispersion equations for single- and multi-layered composite plates, presents a method to efficiently solve complex-valued dispersion equations through standard numerical methods, and proposes a parallel computing technique to enhance computational efficiency of traditional methods. The methodology provided offers a stable, multipurpose, and numerically efficient framework for solving dispersion equations.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Sergey Kuznetsov
Summary: The closed form solutions for guided waves propagating in anisotropic crystals reveal the existence of multiple long-wave limiting velocities, which depend on the wave normal. Numerical examples on the (1,0,0)-plane of cubic crystals show that, for most directions of the wave normal, there are two distinct long-wave limiting velocities, with the possibility of a few directions where two velocities may coincide.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2022)
Article
Mechanics
Antoisse Abdoulatuf, Vu-Hieu Nguyen, Christophe Desceliers, Salah Naili
Summary: This paper presents a new approach to study Lamb-type waves of anisotropic elastic plates in a probabilistic framework. The study investigates the effect of material heterogeneity on Lamb modes by introducing a stochastic model for quantitative description of heterogeneous elastic properties in the plate and performs a sensitivity study on the uncertainty of elasticity properties. The relevance of introducing random media to identify branches associated with experimental dispersion curves is also discussed.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2022)
Article
Mathematics, Applied
Sergey Kuznetsov
Summary: This study reveals for the first time the presence of velocity gaps in the dispersion portraits of guided waves propagating in functionally graded (FG) traction-free plates, indicating the existence of a forbidden phase velocity range where guided waves do not exist. This phenomenon is not observed in homogeneous isotropic or anisotropic plates. The analysis is based on the modified Cauchy sextic formalism and exponential matrix method. The presence of forbidden phase velocities plays a crucial role in the non-destructive diagnostics of functionally graded media by acoustic methods and applications in theoretical geophysics.
ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK
(2022)
Article
Physics, Fluids & Plasmas
B. M. Staples, T. J. Graham, A. P. Hibbins, J. R. Sambles
Summary: Localized acoustic surface waves supported by a soft elastic plate in water were investigated. It was found that for soft interfaces, the energy of the Scholte wave is no longer mainly localized to the water, and the symmetric coupled Scholte mode exhibits dispersive behavior at low frequencies.
Article
Materials Science, Characterization & Testing
Di Sun, Wujun Zhu, Xunlin Qiu, Lishuai Liu, Yanxun Xiang, Fu -Zhen Xuan
Summary: In this paper, a method for accurately detecting closed cracks using nonlinear Lamb waves with phase-velocity mismatching is proposed, which excludes the intrinsic material nonlinearity. Simulations and experimental studies were conducted to analyze the double frequency Lamb waves induced by the closed cracks and the intrinsic material nonlinearity. The results show that the double frequency Lamb waves induced by material nonlinearity are negligible compared to those caused by the contact acoustic nonlinearity of the closed cracks. The proposed method can accurately detect closed cracks, and the acoustic nonlinearity parameter increases monotonically with crack evolution. The findings of this study provide a feasible method for the detection and characterization of closed cracks.
NDT & E INTERNATIONAL
(2023)
Article
Physics, Multidisciplinary
S. Kuznetsov
Summary: It is shown that the dispersion portraits of guided waves propagating in functionally graded isotropic plates with an acoustically softer internal layer may exhibit double crossing of the fundamental branches, which can lead to an intrinsic instability associated with the bifurcation of the corresponding waves. The analysis is based on the modified Cauchy sextic formalism coupled with the exponential matrix method.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Acoustics
Flora Hervin, Paul Fromme
Summary: This study investigates the guided wave propagation behavior of a highly anisotropic unidirectional carbon fiber reinforced polymer laminate. They used finite element analysis and non-contact laser measurements to compare the experimental and numerical results with theoretical predictions. The study emphasizes the importance of accounting for anisotropic effects in guided wave-based structural health monitoring (SHM).
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Engineering, Multidisciplinary
Yuan Liu, Xiaobin Hong, Bin Zhang
Summary: In this paper, a non-elliptical probability imaging (NEPI) method based on nonlinear ultrasonic guided waves is proposed for the delamination damage detection in anisotropic composites. The method is able to accurately display the damage location and has high damage sensitivity.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2023)
Article
Acoustics
F. Hervin, P. Fromme
Summary: Guided ultrasonic wave propagation in anisotropic structures, such as carbon fiber reinforced laminate, can cause directional dependency of velocity and wave skewing effects, affecting the accuracy of damage detection. This study experimentally and through finite element analysis investigated the phase and group velocities of A0 guided wave mode in a unidirectional carbon fiber reinforced laminate. A correction method for the significant offset in phase and group velocities due to wave skewing effects is proposed, achieving good agreement with theoretical calculations assuming planar wave fronts. The influence of the line excitation length on velocity measurements is also discussed.
Article
Engineering, Multidisciplinary
Xianwen Hu, Ching-Tai Ng, Andrei Kotousov
Summary: This study numerically and experimentally investigates the propagation of guided waves in a steel plate with one side partly exposed to water. The results demonstrate that the energy of the quasi-Scholte wave converted by the anti-symmetric Lamb wave decreases with increasing excitation frequency. It is also revealed that the guided wave energy can shift in the frequency domain if the phase velocity of the incident anti-symmetric Lamb wave is larger than the sound speed of water.
Article
Engineering, Mechanical
Qi Yuan, Bence Kato, Keqing Fan, Ying Wang
Summary: Phased array guided wave has great potential for determining damage location and size in plate structures. This study investigates the behavior of phased array guided wave propagation in curved plates through experimental tests and numerical simulations, evaluating the effects of different radii and damage scenarios.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Acoustics
Weibin Li, Changyu Zhang, Mingxi Deng
Summary: In this paper, the modeling and numerical perspectives of zero-group velocity (ZGV) combined harmonic generated by guided waves mixing are investigated. The conditions for the generation of the ZGV combined harmonic are analyzed in an isotropic plate. The study confirms that the ZGV combined harmonic can be generated through counter-directional guided waves mixing, and it can be utilized for localized material degradation assessment with improved signal-to-noise ratio.
Article
Chemistry, Physical
Vykintas Samaitis, Liudas Mazeika
Summary: This paper proposes a phase velocity reconstruction approach based on the phase-shift method, which estimates the velocity at specific frequency harmonics using frequency sweep excitation. The proposed technique is applicable to narrowband piezoelectric transducers and can accurately reconstruct dispersion curves.