共查询到20条相似文献,搜索用时 31 毫秒
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Li Xiaolei Kang Yilan Qiu Wei Xiao Xia 《Acta Mechanica Solida Sinica》2006,19(3):241-247
This paper deals with the mode I crack problem of a cracked rubber sheet under plane stress condition using the delicate digital moire technique. Through the four step phase-shifting method of automated fringe analysis, the displacement fields in the Cartesian coordinate system are given. By the coordinate-transform equation, the radial and circular displacement distributions in the polar coordinate system are obtained. The displacement isoline distributions and displacement vector distributions near the crack tip are discussed. The strain isoline distributions near the crack tip are also analyzed in this paper. Finally, the distribution rules for the mechanical fields near the crack tip are discussed with the sector division method. 相似文献
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An electro-elastic analysis is performed on an icosahedral quasicrystal with piezoelectric effects containing a straight dislocation. The closed-form expressions for the elastic and electric fields are obtained using the extended Stroh formalism. The effects of piezoelectric constant on the phonon displacement, phason displacement, and electric potential are discussed in detail. 相似文献
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H.D. Bui 《Journal of the mechanics and physics of solids》1977,25(1):29-39
The problem of a plane crack of arbibrary shape, subjected to arbitrary loading, is studied. The displacement field is represented by two elastic potentials, the single-layer and the double-layer potential of the second kind. The equations for the crack displacement discontinuities are derived. An approximate analysis of the crack opening displacement under pressure is discussed. 相似文献
6.
A one-dimensional model of fluid displacement in a porous medium is discussed with consideration of lateral inflow. The time period required for the complete displacement of an initially injected fluid from a region is studied. Some numerical results obtained for two formulations of the problem are given; these results are in good agreement with the estimates considered in this paper. The problem under study is of interest in practice for enhancing the oil recovery from oil fields. 相似文献
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《Journal of the mechanics and physics of solids》1986,34(5):499-510
A theoretical analysis is given for the slip-line field in a three-point bend specimen containing a sharp short crack. It is shown that the hydrostatic stresses are larger for deeper cracks. These results support the observation that the crack opening displacement at the initiation of a ductile tear is bigger for shallow cracks than deep ones. An analytical relationship for the ratio of plastic crack tip opening to crack mouth opening displacement is also established which is in agreement with experimental replica measurements. Application of the analysis to practical crack opening displacement measurements for shallow cracks is discussed. 相似文献
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S. K. Deb Nath S. Reaz Ahmed Sung-Gaun Kim 《Archive of Applied Mechanics (Ingenieur Archiv)》2010,80(10):1125-1147
The present paper describes the advancement of displacement potential approach in relation to solution of plane problems of
structural mechanics with mixed mode of boundary conditions. Both the conditions of the plane stress and the plane strain
are considered for analyzing the displacement and stress fields of the structural problem. Using the finite difference technique
based on the present displacement potential approach for the case of the plane stress and the plane strain conditions, firstly
an elastic cantilever beam subjected to a pure shear at its tip is solved and these two solutions (plane stress and plane
strain) are compared with Timoshenko and Goodier cantilever beam bending solutions (Theory of elasticity, 2nd edn. McGraw-Hill,
New York, 1951); secondly the above-mentioned displacement potential approach for the case of the plane stress and the plane
strain conditions are applied to solve a one-end fixed square plate subjected to a combined loading at its tip. Effects of
plane stress and plane strain on the elastic field of the plate are discussed in a comparative fashion. Limitations of Timoshenko
and Goodier cantilever beam bending solutions (Theory of elasticity, 2nd edn. McGraw-Hill, New York, 1951) over the displacement
potential approach for the case of the plane stress and the plane strain conditions are not only discussed but also the superiority
of the present displacement potential approach for the case of the plane stress and the plane strain conditions are reflected
in the present research work. 相似文献
9.
Shuling Hu Shengping Shen Toshihisa Nishioka 《International Journal of Solids and Structures》2007,44(25-26):8457-8492
In this paper, a numerical analysis of impact interfacial fracture for a piezoelectric bimaterial is provided. Starting from the basic equilibrium equation, a dynamic electro-mechanical FEM formulation is briefly presented. Then, the path-independent separated dynamic J integral is extended to piezoelectric bimaterials. Based on the relationship of the path-independent dynamic J integral and the stress and electric displacement intensity factors, the component separation method is used to calculate the stress and electric displacement intensity factors for piezoelectric bimaterials in this finite-element analysis. The response curves of the dynamic J integral, the stress and electric displacement intensity factors are obtained for both homogeneous material (PZT-4 and CdSe) and CdSe/PZT-4 bimaterial. The influences of the piezoelectricity and the electro-mechanical coupling factor on these responses are discussed. The effects of an applied electric field are also discussed. 相似文献
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基于扩展有限元的应力强度因子的位移外推法 总被引:1,自引:0,他引:1
针对平面裂纹问题,阐述了扩展有限元法的单元位移模式、推导了扩展有限元法的控制方程、介绍了特殊单元的数值积分技术.基于最小二乘法,建立了应力强度因子位移外推法的计算公式.利用MATLAB编写计算程序,对平面裂纹问题用扩展有限元法进行了计算.基于扩展有限元法的计算结果,分别利用位移外推法和相互作用积分法,对平面裂纹的应力强度因子进行了计算.计算结果表明,位移外推法比相互作用积分法能更方便和准确地计算平面裂纹的应力强度因子. 相似文献
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A biaxial extensometer for measuring strains in flat cruciform specimens is presented. This extensometer allows for the use of two displacement or strain transducers to control and measure strains along mutually orthogonal directions in the plane of the specimen. The measurement and control of strains along each direction are completely independent of each other. The resolution and the measurable strain range of the biaxial extensometer depend on the particular displacement transducers employed. Independently adjustable gage lengths are incorporated along the two directions such that different strain ranges can be measured with the same transducer displacement range. The use of the biaxial extensometer with cruciform specimens and other applications, including the possibility for measuring triaxial strains in a plate specimen, are discussed. 相似文献
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针对一个瞬变体系进行深入讨论. 分析可得垂直载荷与无量纲垂直位移的三次方成正比,由此引入结构等效拉伸刚度的概念,其值刚好等于结构受水平载荷作用时的刚度;对于结构不对称的情况,基于有限变形理论,给出Lagrange 观点下垂直载荷和位移之间精确表达式,当忽略水平位移时,定义结构的调和长度及等效拉伸刚度,给出统一的载荷与位移之间的关系式. 相似文献
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H. G. Beom Y. H. Kim C. B. Kim C. Cho 《Archive of Applied Mechanics (Ingenieur Archiv)》2008,78(3):191-209
A thin electrode embedded in an electrostrictive material under electric loading is investigated. In order to obtain an asymptotic
form of electric fields and elastic fields near the electrode edge, we consider a modified boundary layer problem of an electrode
in an electrostrictive material under the small scale saturation condition. The exact electric solution for the electrode
is obtained by using the complex function theory. It is found that the shape of the electric displacement saturation zone
is sensitive to the transverse electric displacement. A perturbation solution of stress fields induced by incompatible electrostrictive
strains for the small value of the transverse electric displacement is obtained. The influence of transverse electric displacement
on a microcrack initiation from the electrode edge is also discussed. 相似文献
14.
This paper is concerned with the use of a representation in terms of displacement potentials in second order elasticity for equilibrium problems of homogeneous and isotropic materials. After justifying the adoption of an existing representation for linear elasticity for the purpose at hand, appropriate representations for solutions of second order elasticity problems in terms of displacement potentials (for both compressible and incompressible materials) are discussed. The use of the representations in obtaining complete solutions for equilibrium boundary-value problems is then illustrated by application to two examples of plane strain problems of compressible materials. 相似文献
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Ronald F. Gibson 《Experimental Mechanics》1979,19(10):378-383
This paper describes experimental efforts to measure the time-dependent radial deformations of rotating disks. Although these experiments were concerned with viscoelastic disks, the technique is not limited to this class of materials. The technique is based on the use of an electro-optical displacement follower which tracks the displacement of painted targets on the specimen disk. Associated electronic-compensation circuitry for cancelling the effects of changes in rigid-body motions is also described. The experimental apparatus and developmental problems are discussed and creep measurements are compared with predictions from the technical theory of linear viscoelasticity. 相似文献
16.
Boundary-layer hygrothermal stresses in laminated, composite, circular, cylindrical shell panels 总被引:1,自引:0,他引:1
Free-edge effects in laminated, circular, cylindrical shell panels subjected to hygrothermal loading are studied by utilizing
displacement-based technical theories. Starting from the most general displacement field of elasticity for long, circular,
cylindrical shells, appropriate reduced displacement fields are determined for laminated composite shell panels with cross-ply
and antisymmetric angle-ply layups. An equivalent single-layer shell theory is used to analytically determine the constant
parameters appearing in the reduced displacement fields. A layerwise shell theory is then employed to analytically determine
the local displacement functions and the boundary-layer interlaminar stresses in cross-ply and antisymmetric angle-ply shell
panels under hygroscopic and/or thermal changes. Several numerical examples for the distributions of transverse shear and
normal stresses in various shell panels under a uniform temperature change are presented and discussed. 相似文献
17.
在目前常规图象分辨率基础上,对数字图象相关测量方法的灵敏度进行分析,给出了位移和应变测量的灵敏度,并讨论了影响灵敏度的有关因素,进而指出,数字图象测量系统特别适合于各种位移场的大变形场的定量测量,在配制了相应的光学观察仪器后。也基本适合一般变形场的测量。 相似文献
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利用双材料位移基本解和Somigliana公式,将三维体内含垂直于双材料界面混合型裂纹问题归结为求解一组超奇异积分方程。使用主部分析法,通过对裂纹前沿应力奇性的分析,得到用裂纹面位移间断表示的应力强度因子的计算公式,进而利用超奇异积分方程未知解的理论分析结果和有限部积分理论,给出了超奇异积分方程的数值求解方法。最后,对典型算例的应力强度因子做了计算,并讨论了应力强度因子数值结果的收敛性及其随各参数变化的规律。 相似文献
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SECONDORDEREFFECTSINANELASTICHALF-SPACEACTEDUPONBYANON-UNIFORMNORMALLOADLiuYou-wen(刘又文)(DepartmentofAppliedMathematicsandMech... 相似文献