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椭圆形半露头裂纹的线弹簧模型 总被引:1,自引:0,他引:1
建立了无限平板椭圆形半露头裂纹线弹簧模型,由积分变换方法推导了问题的控制方程和应力强度因子表达式,给出了相应于表面裂纹及内埋裂纹的计算结果,通过与现有有限元解或交替迭代解比较,表明了解的良好性。由此说明半露头裂纹的线弹簧模型解也将是合理的可靠的。 相似文献
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虽然无限弹性体中球腔的动态热应力分布问题已经得到解决,但是对于二维半无限弹性平面内圆形腔孔表面的动态热应力分布问题还没有得到解答。利用复变函数方法,本文分析了在半无限弹性平面附近施加稳态温度场条件下的圆形腔孔表面的动态热应力分布问题,得到了汉克函数表示的此问题的解析解,给出了相应的数值结果并进行了讨论。 相似文献
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本文运用Riemann-Schwarz对称原理导出直边界为固支的半无限平面问题的复变基本解。应用所求得的基本解建立了相 的复变边界积分方程法并给出数据算例。 相似文献
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本文对具有初速的半无限长弹性杆与初始静止的有限长弹性梁的横向冲击问题进行了研究,用伽辽金方法求出了冲击力的近似解析解,并对结果进行了分析和讨论。 相似文献
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本文采用将扇形及四边形塑性区分为三角形和四边形刚性块的有限方法,得到平底模平面正挤压及园冲头压入半无限体的上限解法的极限解,此结果与滑移线法所得结果相符合。 相似文献
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在对运输问题研究成果综述的基础之上,归纳出了多重最优解、有限多重最优解、无限多重最优解、狭义多重最优解以及广义多重最优解等概念.讨论了运输问题多重最优解的进一步分类及判定问题,得到了有限多重最优解和无限多重最优解的判定定理.指正了有关文献中关于多重最优解个数下限的计算公式,给出了有限多狭义多重最优解个数下限的计算公式.最后,举例验证了结论的正确性. 相似文献
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Yufeng Qiao Qibai Huang 《International Journal of Mechanics and Materials in Design》2005,2(3-4):99-112
The sound radiation characteristic from un-baffled rectangular plates is studied in this paper. Both the pressure jump and the transverse displacement of vibrating rectangular plates are also presented. The sound power level radiated from un-baffled plates is numerically calculated by using a double layer integral representation of the sound radiation pressure and the modal coupling coefficients. Rectangular plates with clamped support and elastically support encountered frequently are calculated as numerical experiments. The sound power level radiated from baffled rectangular plates with the same boundary conditions are also calculated in numerical experiments for comparison. From the viewpoint of energy, average velocity square of un-baffled and baffled rectangular plates with␣different boundary conditions is also calculated respectively. The relationship of sound radiation efficiency between un-baffled and baffled rectangular plates is also deduced.This Works is supported by the National Natural
Science Foundation of China (Grant No. 50075029) 相似文献
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This paper extends the numerical method, originally developed by Onate and his colleagues for the static analysis of plates,
to enable modal (vibration) and bifurcative (buckling) analyses of plates to be undertaken. The procedure uses a rotation-free
triangular element, and is based on combining the finite element method and the finite volume method so as to produce a triangular
element with only three displacement degrees of freedom. Elastic stiffness, stability (geometric stiffness) and mass matrices
are developed using the mixed formulation, and these are implemented in routine computer coding in order to demonstrate the
validity and efficacy of the solution technique when compared with results reported by independent investigators. Natural
frequencies and local buckling coefficients are given for plates with interior line supports, and these are used to illustrate
the prowess of the numerical technique for the analysis of a wide class of plate buckling and vibration problems, whose analysis
by non-discretisation techniques has found favour recently in deference to general finite element modelling which tends to
introduce some inaccuracies. The element developed in this paper, however, is both accurate and has the attractive meshing
characteristics of the finite element method for analysing more arbitrary geometric structural topologies. 相似文献
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Stress analysis of perforated composite plates 总被引:1,自引:0,他引:1
Thin-walled plates and panels of various constructions find wide use as primary structural elements in simple and complex configuration. In aerospace structures, panels with variously shaped cutout are often used. The understanding of the effects of cutout on the load bearing capacity and stress concentration of such plates is very important in designing of complex structures. An analytical investigation is used to study the stress analysis of plates with different central cutout. Particular emphasis is placed on flat square plates subjected to a uni-axial tension load. The results based on analytical solution are compared with the results obtained using finite element methods. The main objective of this study is to demonstrate the accuracy and simplicity of presented analytical solution for stress analysis of composite plates with central cutout. The effect of cutout geometry (circular, square, or special cutouts), material properties (isotropic and orthotropic), fiber angles, and cutout curvature are considered. The results presented herein, indicated that the presented method can be used to determine accurately the stresses and stress concentration in composite plates with special shape cutouts. 相似文献
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Reissner厚板的一般解析解答及其应用 总被引:2,自引:1,他引:1
本文基于原始的 Reissner 板模型,根据文献中的控制方程,给出了 Reissner 厚板弯曲问题的一般解析解答形式。在此基础上,详细地讨论了均布荷载下四边固支矩形 Reissner 厚板的弯曲问题,并在 VAX-8200机上编制了相应的 FORTRAN 程序。本文提出的厚板解析方法,无论从力学意义上,还是数学运算上,都比习惯的迭加法简明的多。算例表明:结果可靠、方法可行。 相似文献
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Extending the previous work on isotropic beams and plates by the second author [Li WL, et al. An exact series solution for the transverse vibration of rectangular plates with general elastic boundary supports. J Sound Vib 2009;321:254–69], this paper describes an accurate analytical method for calculating the static deflections and modal characteristics of orthotropic plates with general elastic boundary supports. The displacement function is expressed as a 2-D Fourier cosine series supplemented with several terms in the form of 1-D series. The series expansions for all the relevant derivatives can be directly obtained through term-by-term differentiations of the displacement series. Thus, a classical solution can be derived by letting the series exactly satisfy the governing differential equation at every field point and all the boundary conditions at every boundary point, respectively. Several numerical examples are presented to demonstrate the excellent accuracy and convergence of the current solutions. 相似文献
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In this paper, four methods for the through the thickness response evaluation of laminated composite and sandwich plates are comparatively evaluated in terms of their characteristics and numerical accuracy. The laminated composite and sandwich plates are subjected to thermo-mechanical loading. The four methods include two post-processor-type methods and two re-analysis-type methods. The post-processor-type methods based on the three-dimensional stress equilibrium equations and the three-dimensional thermo-elasticity equations. And the re-analysis methods are based on the incorporation of the nonlinear through the thickness displacements recovered using post-processing technique in the re-analysis phase. The accuracy of the proposed methods for the evaluation of the through the thickness responses of the laminated plates are assessed via numerical examples of various configurations of laminated plates. Also, applicability and computational efficiencies of the methods are discussed.
This research was supported in part by a grant from the BK-21 program for Mechanical and Aerospace Engineering Research at Seoul National University. The authors also gratefully acknowledge the financial support from the Ministry of Science and Technology through the National Laboratory Programs. 相似文献
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Tearing of blast loaded plates with clamped boundary conditions 总被引:3,自引:0,他引:3
Extensive experimental results for the prediction of the onset of thinning (necking) and hence subsequent tearing at the boundary of clamped circular plates subjected to uniformly loaded air blasts are presented. The experiments include: plates of diameter ranging from 60mm to 120mm; different clamped edge conditions; (sharp edge; and radii of 1.5mm and 3.2mm) and an examination of the microstructural behaviour. Observations of thinning at the boundary show similar trends for all plate diameters with sharp edge conditions, and where the boundary edge condition is relaxed the deflections are larger before thinning and tearing occurs. Three phases within Mode I (large inelastic deformation) are identified as; Mode I (no visible necking at the boundary); Mode Ia (necking around part of the boundary); and Mode Ib (necking around the entire boundary). Predictions using the code ABAQUS provide, in particular for Mode I, favourable correlations with the experiments. 相似文献
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Clamped cross-ply plates are analyzed here using a higher-order theory based on a realistic thickness-wise displacement field that accounts for a zig–zag variation of the in-plane displacements. Rigorous analytical solutions are obtained for this difficult problem using a methodology developed recently wherein simple Fourier series solutions of a corresponding simply-supported plate are superposed, each such component solution being summed without truncation using MATHEMATICA. Numerical results, for square homogeneous and three-layer plates under uniform and central point loads, are compared with those based on the classical and first-order theories. 相似文献