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Acta Mechanica Sinica 2021年第5期37卷 803-825,I0002页

作者： Zhi-Hua He Yi-Ze wang yue-sheng wang Institute of Engineering Mechanics Beijing Jiaotong UniversityBeijing 100044China Department of Mechanics Tianjin UniversityTianjin 300350China

Due to their potential properties unlike traditional materials and structures,elastic wave metamaterials have received significant interests in recent *** the coupling between the acoustic and vibration,their mechanical characteristics can be tuned by the active feedback control system at low frequency ranges in which the traditional passive control is *** work illustrates that the superior performances of the effective mass density and sound pressure level(SPL)of an elastic wave metamaterial can be significantly changed by the active control,in which the periodic array of local resonators and orthogonal stiffeners are ***,based on the locally resonant mechanism,the negative density occurs over a frequency *** to the effects of lattice constant,structural damping and other parameters,the SPL with the function of fluid-solid coupling are illustrated and discussed.

关键词： Elastic wave metamaterial Local resonance Sound radiation Fluid-solid coupling Active feedback control

Sound Transmission Comparisons of Active Elastic Wave Metamaterial Immersed in External Mean Flow

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Acta Mechanica Solida Sinica 2021年第3期34卷 307-325页

作者： Zhi-Hua He Yi-Ze wang yue-sheng wang Institute of Engineering Mechanics Beijing Jiaotong UniversityBeijing 100044China Department of Mechanics Tianjin UniversityTianjin 300350China

Using the active feedback control system on the elastic wave metamaterial,this research concentrates on the sound transmission with the dynamic effective *** metamaterial is subjected to an incident pressure and immersed in the external mean *** elastic wave metamaterial consists of double plates and the upper and lower four-link mechanisms are attached *** vertical resonator is attached by the active feedback control system and connected with two four-link *** on the dynamic equivalent method,the metamaterial is equivalent as a single-layer plate by the dynamic effective *** the coupling between the fluid and structure,the expression of the sound transmission loss(STL)is *** research shows the influence of effective mass density on sound transmission properties,and the STL in both modes can be tuned by the acceleration and displacement feedback *** addition,the dynamic response and the STL are also changed obviously by different values of structural damping,incident angle(i.e.,the elevation and azimuth angles)and Mach number of the external fluid with the mean flow *** results for sound transmission by two methods are compared,i.e.,the virtual work principle for double plates and the dynamic equivalent method corresponding to a single *** paper is expected to be helpful for understanding the sound transmission properties of both pure single-and double-plate models.

关键词： Elastic wave metamaterials Active feedback control Dynamic equivalent method Sound transmission External mean flow

Band structure properties of elastic waves propagating in the nanoscaled nearly periodic layered phononic crystals

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Acta Mechanica Solida Sinica 2017年第2期30卷 113-122页

作者： A-Li Chen Li-Zhi Tian yue-sheng wang Institute of Engineering Mechanics Beijing Jiaotong Uniuersity Beijing 100044 China

The localization factor is used to describe the band structures for P wave propagating normally in the nanoscaled nearly periodic layered phononic crystals. The localization factor is calculated by the transfer matrix method based on the nonlocal elastic continuum *** kinds of nearly periodic arrangements are concerned, i.e., random disorder, quasiperiodicity and defects. The influences of randomly disordered degree of the sub-layer＇s thickness and mass density, the arrangement of quasi-periodicity and the location of defect on the band structures and cut-off frequency are analyzed in detail.

关键词： Elastic wave Nanoscale Nearly periodic Phononic crystal Band structure

Analytical solution of axisymmetric contact problem about indentation of a circular indenter into a soft functionally graded elastic layer

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Acta Mechanica Sinica 2013年第2期29卷 196-201页

作者： Sergey Volkov Sergey Aizikovich yue-sheng wang Igor Fedotov Research and Education Center "Materials" Don State Technical University South Federal University Research Institute of Mechanics and Applied Mathematics Institute of Engineering Mechanics Beijing Jiaotong University Department of Mathematical Technology Tshwane University of Technology

The paper addresses a contact problem of the theory of elasticity,i.e.,the penetration of a circular indenter with a flat base into a soft functionally graded elastic *** elastic properties of a functionally graded layer arbitrarily vary with depth,and the foundation is assumed to be elastic,yet much harder than a *** analytical solution is constructed,and it is shown that the solutions are asymptotically exact both for large and small values of characteristic dimensionless geometrical parameter of the *** examples are analyzed for the cases of monotonic and nonmonotonic variations of elastic *** results for the case of homogeneous layer are compared with the results for nondeformable foundation.

关键词： Contact problems·Indentation·Functionally graded layer

Free vibration of size-dependent magneto-electro-elastic nanoplates based on the nonlocal theory

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Acta Mechanica Sinica 2014年第4期30卷 516-525页

作者： Liao-Liang Ke yue-sheng wang Jie Yang Sritawat Kitipornchai Institute of Engineering Mechanics Beijing Jiaotong University School of Civil Engineering The University of QueenslandSt Lucia QLD 4072 Australia School of Aerospace Mechanical and Manufacturing EngineeringRMIT University

In this paper, the free vibration of magneto- electro-elastic （MEE） nanoplates is investigated based on the nonlocal theory and Kirchhoff plate theory. The MEE nanoplate is assumed as all edges simply supported rectan gular plate subjected to the biaxial force, external electric potential, external magnetic potential, and temperature rise. By using the Hamilton＇s principle, the governing equations and boundary conditions are derived and then solved analytically to obtain the natural frequencies of MEE nanoplates. A parametric study is presented to examine the effect of the nonlocal parameter, thermo-magneto-electro-mechanical loadings and aspect ratio on the vibration characteristics of MEE nanoplates. It is found that the natural frequency is quite sensitive to the mechanical loading, electric loading and magnetic loading, while it is insensitive to the thermal loading.

关键词： Magneto-electro-elastic materials Nanoplates ·Nonlocal theory Vibration

The axisymmetric torsional contact problem of a functionally graded piezoelectric coated half-space

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Acta Mechanica Sinica 2017年第2期33卷 406-414页

作者： Jie Su Liao-Liang Ke yue-sheng wang Yang Xiang Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China School of Computing Engineering and MathematicsWestern Sydney University Penrith South NSW 2751 Australia Centre for Infrastructure Engineering Western Sydney University Penrith South NSW 2751 Australia

In this article, we study the axisymmetric torsional contact problem of a half-space coated with functionally graded piezoelectric material (FGPM) and subjected to a rigid circular punch. It is found that, along the thickness direction, the electromechanical properties of FGPMs change exponentially. We apply the Hankel integral transform technique and reduce the problem to a singular integral equation, and then numerically determine the unknown contact stress and electric displacement at the contact surface. The results show that the surface contact stress, surface azimuthal displacement, surface electric displacement, and inner electromechanical field are obviously dependent on the gradient index of the FGPM coating. It is found that we can adjust the gradient index of the FGPM coating to modify the distributions of the electric displacement and contact stress.

关键词： Axisymmetric torsional contact Singular integral equation Functionally graded piezoelectric materials (FGPMs)

Historical perspective of syphilis in the past 60 years in China： eliminated, forgotten, on the return

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Chinese Medical Journal 2013年第14期126卷 2774-2779页

作者： CHEN Xiang-sheng YIN yue-ping wang Qian-qiu wang Bao-xi National Center for STD Control and Institute of Dermatology Chinese Academy of Medical Sciences and Peking Union Medical College Nanjing Jiangsu 210042 China

Syphilis （historically called lues） is a sexually transmitted disease （STD） caused by the spirochete bacteriumTreponema pallidum subspecies pallidum. Syphilis had many alternate names, such as the ＂great pox＂ in order to distinguish it from smallpox, and was given many national attributions, such as the French pox, the English pox, and the Italian pox, due to the disease often being spread by foreign sailors and soldiers during their frequent,

关键词： syphilis epidemic elimination control

Molecular Dynamics Simulations of the Orientation Effect on the Initial Plastic Deformation of Magnesium Single Crystals

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Acta Metallurgica Sinica(English Letters) 2016年第3期29卷 301-312页

作者： Qun Zu Ya-Fang Guo Shuang Xu Xiao-Zhi Tang yue-sheng wang Institute of Engineering Mechanics Beijing Jiaotong University School of Science Wuhan University of Technology

Molecular dynamics simulation is employed to study the tension and compression deformation behaviors of magnesium single crystals with different *** angle between the loading axis and the basal direction ranges from 0° to 90°.The simulation results show that the initial defects usually nucleate at free surfaces,but the initial plastic deformation and the subsequent microstructural evolutions are various due to different loading *** tension simulations exhibit the deformation mechanisms of twinning,slip,crystallographic reorientation and basal/prismatic *** twinning,crystallographic reorientation and basal/prismatic transformation can only appear in the crystal model loaded along or near the a-axis or *** the compression simulations,the basal,prismatic and pyramidal slips are responsible for the initial plasticity,and no twinning is ***,the plastic deformation models affect the yield strengths for the samples with different *** maximum yield stresses for the samples loaded along the c-axis or a-axis are much higher than those loaded in other directions.

关键词： Molecular dynamics simulations Magnesium Plastic deformation Orientation

Propagation of flexural waves in phononic crystal thin plates with linear defects

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第10期11卷 827-834页

作者： Zong-jian YAO Gui-lan YU yue-sheng wang Zhi-fei SHI Jian-bao LI School of Civil Engineering Beijing Jiaotong University Beijing 100044 China

The band structures of flexural waves in a phononic crystal thin plate with straight, bending or branching linear defects are theoretically investigated using the supercell technique based on the improved plane wave expansion method. We show the existence of an absolute band gap of the perfect phononic crystal and linear defect modes inside the gap caused by localization of flexural waves at or near the defects. The displacement distributions show that flexural waves can transmit well along the straight linear defect created by removing one row of cylinders from the perfect phononic crystals for almost all the frequencies falling in the band gap, which indicates that this structure can act as a high efficiency waveguide. However, for bending or branching linear defects, there exist both guided and localized modes, and therefore the phononic crystals could be served as waveguides or filters.

关键词： Phononic crystal Thin plates Linear defects Flexural waves

Bandgap calculation for mixed in-plane waves in 2D phononic crystals based on Dirichlet-to-Neumann map

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Acta Mechanica Sinica 2012年第4期28卷 1143-1153页

作者： Ni Zhen Feng-Lian Li yue-sheng wang Chuan-Zeng Zhang Institute of Engineering Mechanics Beijing Jiaotong University100044 BeijingChina Department of Civil Engineering University of SiegenSiegenD-57068Germany

In this paper, a method based on the Dirichlet- to-Neumann map is developed for bandgap calculation of mixed in-plane waves propagating in 2D phononic crystals with square and triangular lattices. The method expresses the scattered fields in a unit cell as the cylindrical wave expansions and imposes the Bloch condition on the boundary of the unit cell. The Dirichlet-to-Neumann （DtN） map is applied to obtain a linear eigenvalue equation, from which the Bloch wave vectors along the irreducible Brillouin zone are calculated for a given frequency. Compared with other methods, the present method is memory-saving and time-saving. It can yield accurate results with fast convergence for various material combinations including those with large acoustic mismatch without extra computational cost. The method is also efficient for mixed fluid-solid systems because it considers the different wave modes in the fluid and solid as well as the proper fluid-solid interface condition.

关键词： Phononic crystal Band structure Cylindrical wave expansion Dirichlet-to-Neumann (DtN) map Bloch theorem