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Theoretical and numerical investigation of HF elastic wave propagation in two-dimensional periodic beam lattices

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Acta Mechanica Sinica 2013年第6期29卷 783-798页

作者： B.Tie B.Y.Tian D.Aubry Laboratory MSSMat(UMR-CNRS 8579) Ecole Centrale ParisGrande Voie des Vignes92295 Chatenay-Malabry CedexFrance

The elastic wave propagation phenomena in two-dimensional periodic beam lattices are studied by using the Bloch wave transform. The numerical modeling is applied to the hexagonal and the rectangular beam lattices, in which, both the in-plane （with respect to the lattice plane） and out-of-plane waves are considered. The dispersion relations are obtained by calculating the Bloch eigenfrequencies and eigenmodes. The frequency bandgaps are observed and the influence of the elastic and geometric properties of the primitive cell on the bandgaps is studied. By analyzing the phase and the group velocities of the Bloch wave modes, the anisotropic behaviors and the dispersive characteristics of the hexagonal beam lattice with respect to the wave prop- agation are highlighted in high frequency domains. One im- portant result presented herein is the comparison between the first Bloch wave modes to the membrane and bend- ing/transverse shear wave modes of the classical equivalent homogenized orthotropic plate model of the hexagonal beam lattice. It is shown that, in low frequency ranges, the homog- enized plate model can correctly represent both the in-plane and out-of-plane dynamic behaviors of the beam lattice, its frequency validity domain can be precisely evaluated thanks to the Bloch modal analysis. As another important and original result, we have highlighted the existence of the retro- propagating Bloch wave modes with a negative group veloc- ity, and of the corresponding ＂retro-propagating＂ frequency bands.

关键词： elastic wave propagation Periodic beam lattice Bloch wave theory Bandgaps Anisotropy Disper- sion relation

Finite element equations and numerical simulation of elastic wave propagation in two-phase anisotropic media

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Acta Seismologica Sinica(English Edition) 2003年第2期16卷 166-174页

作者：刘洋魏修成 CNPCGeophysicalKeyLab UniversityofPetroleum

Based on Biot theory of two-phase anisotropic media and Hamilton theory about dynamic problem,finite element equations of elastic wave propagation in two-phase anisotropic media are derived in this *** solution of fin... 详细信息

关键词： two-phase anisotropic media elastic wave propagation finite element equations numerical simulation

Effect of negative permeability on elastic wave propagation in magnetoelastic multilayered composites

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Theoretical & Applied Mechanics Letters 2017年第3期7卷 126-133页

作者： W. Wang Y.Q. Guo W.Q. Chen Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education and School of Civil Engineering and MechanicsLanzhou University Lanzhou 730000 China Department of Engineering Mechanics Yuquan Campus Zhejiang University Hangzhou 310027 China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Hangzhou 310027 China

With the advent of left-handed magnetic materials, it is desirable to develop high-performance wave devices based on their novel properties of wave propagation. This letter reports the special properties of elastic wave propagation in magnetoelastic multilayered composites with negative permeability as compared to those in counterpart structures with positive permeability. These novel properties of elastic waves are discerned from the diversified dispersion curves, which represent the propagation and attenuation characteristics of elastic waves. To compute these dispersion curves, the method of reverberation-ray matrix is extended for the analysis of elastic waves in magnetoelastic multilayered composites. Although only the results of a single piezomagnetic and a binary magnetoelastic layers with mechanically free and magnetically short surfaces as well as perfect interface are illustrated in the numerical examples, the analysis is applicable to magnetoelastic multilayered structures with other kinds of boundaries/interfaces.

关键词： Magnetoelastic multilayered composites elastic wave propagation Method of reverberation-ray matrix Negative permeability wave mode conversion

An improvement in the absorbing boundary technique for numerical simulation of elastic wave propagation

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An improvement in the absorbing boundary technique for numer...

Modeling of wheel-rail coupling contact by submodeling technique for elastic wave propagation

中国科学院地质与地球物理研究所2008学术年会

作者： Ik Bum Kang Geun Young Kim Earthquake Research Center Environmental Geology DivisionKorea Institute of Geoscience & Mineral ResourcesDaejeon305-350Korea

The computational domain is artificially designed in the numerical simulation of elastic waves propagating in unbounded *** a result,boundary reflections arise from the edges of such truncated *** many complex schemes have been developed to solve this problem,the absorbing boundary technique of Cerjan et al(1985 Geophysics 50 705-8),as the simplest,is still widely used,especially for the pseudospectral *** improve the efficiency of suppressing such boundary reflections in the simple technique,we apply damping to the movement velocity of nodes in a narrow strip along the *** modelling results demonstrate its greater effectiveness than previous treatments which apply the damping to the displacement or both displacement and movement velocity of nodes.

关键词： boundary condition elastic wave propagation numerical simulation

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Modeling of wheel-rail coupling contact by submodeling techn...

Symplectic analysis for wave propagation in one-dimensional nonlinear periodic structures

第36届中国控制会议

作者： Kangwei Wang Xin Zhang Yamei Yue Yan Wang Yi Shen Department of Control Science and Engineering Harbin Institute of Technology Department of Mechatronics Engineering Harbin Institute of Technology

ISBN: (纸本)9781538629185

Acoustic emission（AE） technique is an emerging nondestructive inspection method for rail *** the detection distance for AE sensors is too short and it’s infeasible to monitor an entire *** a replacing scheme,it’s effective to place the sensors in the wheels,which make the study of wave propagation between elastic bodies *** this paper,the model of wheel-rail coupling contact is based on finite element（FE） method and the results are compared with theoretical values calculated by Hertz contact theory to ensure the validity of the *** technique is adopted in the FE model to obtain a more detailed *** the strength of the built model,the elastic wave propagation is imported and signals received in the wheel and rail are *** results illustrate that the elastic wave generated by the source in the rail has successfully propagated into the wheel and can be *** built model can be used for the search of more elastic wave propagation problems.

关键词： Hertz contact finite element analysis elastic wave propagation submodeling technique

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Applied Mathematics and Mechanics(English Edition) 2010年第11期31卷 1371-1382页

作者：侯秀慧邓子辰周加喜 Department of Engineering Mechanics Northwestern Polytechnical University State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology College of Mechanical and Vehicle Engineering Hunan University

The wave propagation problem in the nonlinear periodic mass-spring structure chain is analyzed using the symplectic mathematical method. The energy method is used to construct the dynamic equation, and the nonlinear dynamic equation is linearized using the small parameter perturbation method. Eigen-solutions of the symplectic matrix are used to analyze the wave propagation problem in nonlinear periodic lattices. Nonlinearity in the mass-spring chain, arising from the nonlinear spring stiffness effect, has profound effects on the overall transmission of the chain. The wave propagation characteristics are altered due to nonlinearity, and related to the incident wave intensity, which is a genuine nonlinear effect not present in the corresponding linear model. Numerical results show how the increase of nonlinearity or incident wave amplitude leads to closing of transmitting gaps. Comparison with the normal recursive approach shows effectiveness and superiority of the symplectic method for the wave propagation problem in nonlinear periodic structures.

关键词： symplectic mathematical method nonlinear periodic structure elastic wave propagation

A lumped mass Chebyshev spectral element method and its application to structural dynamic problems

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Earthquake Engineering and Engineering Vibration 2022年第3期21卷 843-859页

作者： Wang Jingxiong Li Hongjing Xing Haojie Engineering Mechanics Institute Nanjing Tech UniversityNanjing 211816China Institute of Geophysics China Earthquake AdministrationBeijing 100081China

A diagonal or lumped mass matrix is of great value for time-domain analysis of structural dynamic and wave propagation problems,as the computational efforts can be greatly reduced in the process of mass matrix *** this study,the nodal quadrature method is employed to construct a lumped mass matrix for the Chebyshev spectral element method(CSEM).A Gauss-Lobatto type quadrature,based on Gauss-Lobatto-Chebyshev points with a weighting function of unity,is thus *** the aid of this quadrature,the CSEM can take advantage of explicit time-marching schemes and provide an efficient new tool for solving structural dynamic *** types of lumped mass Chebyshev spectral elements are designed,including rod,beam and plate *** performance of the developed method is examined via some numerical examples of natural vibration and elastic wave propagation,accompanied by their comparison to that of traditional consistent-mass CSEM or the classical finite element method(FEM).Numerical results indicate that the proposed method displays comparable accuracy as its consistent-mass counterpart,and is more accurate than classical *** the simulation of elastic wave propagation in structures induced by high-frequency loading,this method achieves satisfactory performance in accuracy and efficiency.

关键词： mass lumping Chebyshev spectral element method Gauss-Lobatto-Chebyshev points Gauss-Lobatto type quadrature structural dynamic analysis elastic wave propagation

Bandgap Analysis of Periodic Composite Microplates with Curvature-Based Flexoelectricity:A Finite Element Approach

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Acta Mechanica Solida Sinica 2022年第6期35卷 996-1003页

作者： Pengyu Lai Zhangzhang He Yu Cong Shuitao Gu Gongye Zhang School of Civil Engineering Chongqing UniversityChongqing400044China Jiangsu Key Laboratory of Engineering Mechanics School of Civil EngineeringSoutheast UniversityNanjing210096China University Paris-Saclay Univ EvryLMEE91020EvryFrance

A finite element model is proposed permitting prediction of elastic wave bandgaps of periodic composite microplates incorporating flexoelectric *** this model,we applied curvature-based flexoelectricity and Mindlin plate theories and derived a finite element formulation that has been implemented for bandgap *** finite element model utilizes a three-node triangle element with 30 degrees of freedom satisfying Mindlin kinematics *** is based on a non-conforming interpolation scheme which provides nodal C^(1) continuity and ensures compatibility with curvature-based *** approach accounts for microstructure effects and,owing to the triangular element topology,can be used to assist the design of microplates with complex *** of the approach is performed through comparison with both analytical and numerical models,in which the effect of flexoelectricity on the bandgap is studied based on cases demonstrating size dependence.

关键词： Bandgap elastic wave propagation Metamaterial design Curvature-based flexoelectricity Mindlin plate finite element

Analysis of the Attenuation Characteristics of an elastic wave Due to the wave-Induced Fluid Flow in Fractured Porous Media

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Chinese Physics Letters 2014年第4期31卷 76-80页

作者： WANG Ding WANG Li-Ji ZHANG Mei-Gen Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of sciences Beijing 100029 Ur~iversity of Chinese Academy of Sciences Beijing 100049

A theoretical model is presented to describe the elastic wave propagation characteristics in porous media of periodically arranged fractures. The effects of fracture geometric parameters on a compressional wave （p-wave） are considered through analysis of the wave induced fluid flow （WIFF） process between the fractures and the background media. The diffusion equation in porous media is used to reveal how the entire diffusion process affects the wave propagation. When the thickness proportion of fractures tends to 0 and 1, the WIFF does not take place almost between fractures and background matrix porosity, and therefore the media elasticity modulus is perfectly elastic. When the fracture thickness fraction achieves a certain value, the peak of the attenuation curve reaches the maximum value at a particular frequency, which is controlled by the fluid mass conservation and stress continuity conditions on each fracture boundary. That is, the inter-coupling of fluid diffusion between the adjacent layers is important for waves attenuation. Physically speaking, the dissipation of a wave is associated with the fluid flux essentially.

关键词： POROUS materials elastic wave propagation ATTENUATION (Physics) MICROwaveS -- Attenuation elastic waves