检索结果-南通市图书馆

Acta Mechanica Solida Sinica 2020年第4期33卷 496-507页

作者： Zhichao Zhang Shirong Liu School of Civil Engineering and Science Yangzhou UniversityYangzhou 225127China

Thermoelastic damping(TED)is one of the main internal energy dissipation mechanisms in micro/*** evaluation of TED is important in the design of micro-electromechanical systems and nano-electromechanical *** this paper,a theoretical analysis on the TED in functionally graded material(FGM)micro-beam resonators is *** of motion and the heat conduction equation governing the thermodynamic coupling free vibration of non-homogenous micro-beams are established based on the Euler Bernoulli beam theory associated with the modified couple stress *** properties of the FGM micro-beam are assumed to change in the depth direction as power-law *** layer-wise homogenization method is used for solving the heat conduction *** using the mathematical similarity of eigenvalue problem between the FGM beam and the reference homogeneous one,the complex natural frequency including TED is expressed in terms of the natural frequency of the isothermal homogenous *** the presented numerical results,influences of various characteristic parameters,such as beam thickness,material gradient index,structure size,vibration mode and boundary conditions,on TED are examined in *** shows that TED decreases with the increases in the values of length scale parameters because the latter lead to the increase in structural stiffness.

关键词： functionally graded material Size dependent Thermoelastic damping Micro-beam

Calculation of the Composition Profile of a functionally graded material Produced by Co-sedimentation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2003年第1期19卷 57-59页

作者： ZhongminYANG LianmengZHANG 等 StateKeyLab.ofAdvancedTechnologyformaterialsSynthesisandProcessing WuhanUniversityofTechnologyWuhan430070Chian StateKeyLab.ofAdvancedTechnologyformaterialsSynthesisandProcessing WuhanUniversityofTec

A sedimentation method is proposed to fabricate functionally graded materials (FGMs) with the continuous andsmooth variations of composition. The relations between the compositional distribution of deposited body and thepowder characteristics of raw materials as well as settling parameters are derived. Subsequently, the mathematicalmodel of forming FGM based on the co-sedimentation has been established. At last, numerical simulations areconducted to explore the effects of the particle sizes of raw materials and suspension height on the compositionaldistribution of final products.

关键词： Calculation functionally graded material Co-sedimentation

Free vibration of functionally graded material beams with surface-bonded piezoelectric layers in thermal environment

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2009年第8期30卷 969-982页

作者：李世荣苏厚德程昌钧 Department of Engineering Mechanics Lanzhou University of Technology Department of Mechanics Shanghai University

Free vibration of statically thermal postbuckled functionally graded material （FGM） beams with surface-bonded piezoelectric layers subject to both temperature rise and voltage is studied. By accurately considering the axial extension and based on the Euler-Bernoulli beam theory, geometrically nonlinear dynamic governing equations for FGM beams with surface-bonded piezoelectric layers subject to thermo-electro- mechanical loadings are formulated. It is assumed that the material properties of the middle FGM layer vary continuously as a power law function of the thickness coordinate, and the piezoelectric layers are isotropic and homogenous. By assuming that the amplitude of the beam vibration is small and its response is harmonic, the above mentioned non-linear partial differential equations are reduced to two sets of coupled ordinary differential equations. One is for the postbuckling, and the other is for the linear vibration of the beam superimposed upon the postbuckled configuration. Using a shooting method to solve the two sets of ordinary differential equations with fixed-fixed boundary conditions numerically, the response of postbuckling and free vibration in the vicinity of the postbuckled configuration of the beam with fixed-fixed ends and subject to transversely nonuniform heating and uniform electric field is obtained. Thermo-electric postbuckling equilibrium paths and characteristic curves of the first three natural frequencies versus the temperature, the electricity, and the material gradient parameters are plotted. It is found that the three lowest frequencies of the prebuckled beam decrease with the increase of the temperature, but those of a buckled beam increase monotonically with the temperature rise. The results also show that the tensional force produced in the piezoelectric layers by the voltage can efficiently increase the critical buckling temperature and the natural frequency.

关键词： functionally graded material laminated beams with piezoelectric layers thermal buckling free vibration natural frequency

Fabrication and Microstructure of W/Cu functionally graded material

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2001年第3期8卷 198-202页

作者： Yunhan Ling, Jiangtao Li, Zhangjian Zhou, Changchun Ge Laboratory of Special Ceramics & Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083, China Lab. of Spec. Ceram. and Powd. Meta. Univ. of Sci. and Technol. Beijing Beijing 100083 China

W/Cu functionally gradient material (FGM) has excellent mechanical properties since it can effectively relax interlayer thermal stresses caused by the mismatch between their thermal expansion coefficients. W/Cu FGM combines the advantages of tungsten such as high melting point and service strength, with heat conductivity and plasticity of copper at room temperature. Thus it demonstrates satisfactory heat corrosion and thermal shock resistance and will be a promising candidate as divertor component in thermonuclear device. Owing to the dramatic difference of melting point between tungsten and copper, conventional processes meet great difficulties in fabricating this kind of FGMs. A new approach termed graded sintering under ultra-high pressure (GSUHP) is proposed, with which a near 96% relative density of W/Cu FGM that contains a full distribution spectrum (0-100%W) has been successfully fabricated. Suitable amount of transition metals (such as nickel, zirconium, vanadium) is employed as additives to activate tungsten's sintering, enhance phase wettability and bonding strength between W and Cu. Densification effects of different layer of FGM were investigated. Microstructure morphology and interface elements distribution were observed and analyzed. The thermal shock performance of W/Cu FGM was also preliminarily tested.

关键词： tungsten copper sintering functionally graded material composite

3D analysis of functionally graded material plates with complex shapes and various holes

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2009年第1期30卷 13-18页

作者：曹志远唐寿高程国华 School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092 P. R. China

In this paper, the basic formulae for the semi-analytical graded FEM on FGM members are derived. Since FGM parameters vary along three space coordinates, the parameters can be integrated in mechanical equations. Therefore with the parameters of a given FGM plate, problems of FGM plate under various conditions can be solved. The approach uses 1D discretization to obtain 3D solutions, which is proven to be an effective numerical method for the mechanical analyses of FGM structures. Examples of FGM plates with complex shapes and various holes are presented.

关键词： functionally graded material semi-analytical method complex shape 3D analysis hole

Chebyshev-Lagrange Multipliers Technique for Vibration Analysis of functionally graded material Beams using Various Beam Theories

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2022年第4期14卷 871-892页

作者： Sacharuck Pornpeerakeat Sakda Katawaethwarag Department of Teacher Training in Civil Engineering King Mongkut’s University of Technology North BangkokBangkok10800Thailand Research Centre for Advanced Computational and Experimental Mechanics(RACE) King Mongkut’s University of Technology North BangkokBangkok10800Thailand

In this paper,a new technique for analysing functionally graded material(FGM)beams using the Chebyshev polynomials and Lagrange multipliers with various beam theories is *** utilizing the inner products and the Chebyshev polynomials’orthogonality properties incorporated with Lagrange multipliers,we can combine the governing equation and boundary conditions to yield the matrix equations with explicit weighting *** examples are provided for vibration analysis of various beam theories and *** on numerical evaluations,it is revealed that the proposed technique can efficiently achieve good agreement with those of the references.

关键词： Chebyshev polynomials Lagrange multipliers functionally graded material orthogonality vibration analysis.

Stress concentration in a finite functionally graded material plate

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2012年第7期55卷 1263-1271页

作者： YANG QuanQuan GAO CunFa CHEN WenTao State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics&AstronauticsNanjing 210016China

This paper is to study the two-dimensional stress distribution of a finite functionally graded material (FGM) plate with a circular hole under arbitrary constant loads. Using the method of piece-wise homogeneous layers, the stress analysis of the finite FGM plate having radial arbitrary elastic properties is made based on the complex variable method combined with the least square boundary collocation technique. Numerical results of stress distribution around the hole are then presented for different loading conditions, different material properties and different plate sizes, respectively. It is shown that the stress concentration in the finite plate is generally enhanced compared with the case of an infinite plate, but it can be significantly reduced by choosing proper change ways of the radial elastic modulus.

关键词： functionally graded material f'mite plate circular hole stress concentration

Sound radiation of a functionally graded material cylindrical shell in water by mobility method

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2011年第6期1卷 69-74页

作者： Buqing Xu,1,2, ) Shaopu Yang,3, and Haoyu Li1, 1)Department of Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang 050043, China 2)Provincial Laboratory of Traffic Safety and Control of Hebei, Shijiazhuang Tiedao University, Shijiazhuang 050043, China 3)Shijiazhuang Tiedao University, Shijiazhuang 050043, China Shijiazhuang Tiedao Univ Dept Engn Mech Shijiazhuang 050043 Hebei Peoples R China Shijiazhuang Tiedao Univ Prov Lab Traff Safety & Control Hebei Shijiazhuang 050043 Hebei Peoples R China Shijiazhuang Tiedao Univ Shijiazhuang 050043 Hebei Peoples R China

Based on the fundamental dynamic equations of functionally graded material (FGM) cylindrical shell, this paper investigates the sound radiation of vibrational FGM shell in water by mobility method. This model takes into account the exterior fluid loading due to the sound press radiated by the FGM shell. The FGM cylindrical shell was excited by a harmonic line radial force uniformly distributing along the generator. The FGM shell equations of motion, the Helmholtz equation in the exterior fluid medium and the continuity equation at fluid-shell interface are used in this vibroacoustic problem. The expressions of sound radiation efficiency and sound field of the FGM shell have been derived by mobility method. Radiation efficiency, modal mobility and the directivity pattern of the sound field are solved numerically. In particular, radiation efficiency and directivity pattern with various power law index are analyzed.

关键词： fluid-loaded cylindrical shell functionally graded material mobility method sound radiation

Titanium/Hydroxyapatite Composite and functionally graded material Fabricated By Three-Dimensional Printing

在线全文

学校读者我要写书评

暂无评论

Titanium/Hydroxyapatite Composite and Functionally Graded Ma...

Stress concentration around a circular hole in a functionally graded material finite plate

中华口腔医学会第14次全国口腔医学学术会议（2012年会）

作者： Qian Chao,Sun Jian (Dept.of Prosthodontics,The Ninth People’s Hospital,School of Medicine,Shanghai Jiao Tong University,Shanghai 200011,China Shanghai Key Laboratory of Stomatology,Shanghai 200011,China)

Purpose:The aim of this study was to evaluate the feasibility of three-dimensional printing technology for the preparation and fabricate titanium/hydroxyapatite(Ti/HA)composite and functionally graded material(FGM)by three-dimensional printing,which providing the foundation theories and experimental bases of functionally graded material from designing,modeling,sintering and the performance evaluation. Methods:The CAD model of the Green Ti/HA composite was designed to be the cylinder(diameter 25mm,height 20mm)and set each layer with 100%bond area. The Ti/HA functionally graded material sample was divided into two layers,the upper layer with 100%Ti and the lower layer with 80%Ti/20%HA,which also design to be a CAD model of the cylinder with 25mm in diameter and 10 mm in *** three dimensional printing technology was used to process five specimens of 80%Ti/20%HA and three FGM *** process was comprised by debind sintering and the final *** specimens were first debinded under vacuum with 500℃.Then they were sintered under the protection of the argon gas with 1200℃*** sintered 80%Ti/20%HA composites were observed their microstructure,analyzed the diffraction element and tested in mechanical properties such as compressive *** the microstructure of sintered FGM specimens was also observed. Resu I ts:The sintered 80%Ti/20%HA specimens had the aperture size from 50 to 150μ*** XRD analysis of Ti/HA composite showed the characteristic peak contains Ca(PO),CaTiO,TiO and CaO features,which pointed that there occurred a chemical reaction between Ti and *** compressive strength was 184.3±*** Ti/HA functionally graded material,with its upper part for 80%Ti/20%HA layer and lower layer of 100%Ti,had graded structures with a visible decomposition of a clearer line between the two layers under the optical microscope. Conclusion:*** is confirmed that application of Ti/HA composite and functionally graded material fabricate

关键词： three dimensional printing titanium hydroxyapatite functionally graded material

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Stress concentration around a circular hole in a functionall...