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571.
This work is concerned with the Saint-Venant torsion problem of a two-phase circumferentially symmetric compound prismatic
bar. By generalizing a method originally proposed by Packham and Shail [12], we demonstrate that for a particular two-phase
configuration, simply or multiply connected, which is invariant with phase interchange, the solutions can be constructed from
solutions of two analogous problems with constant material properties. An effective shear modulus is derived in analytic form,
which is approximately the harmonic mean of the component shear moduli. We also show that the effective torsional shear modulus
is homogeneous for arbitrary configurations.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
572.
本文对不同刚度、不同长度、不同支承条件的具有对称截面的重叠梁,在任何载荷作用下产生的弯扭变形而引起的接触问题进行了分析,导出了单侧线接触、双侧线接触时的压力分布规律及点接触定理;给出了一个静不定梁算例,当外载变化时将出现单侧接触区、双侧接触区与点接触的复杂情况,而数值计算描述了当外载增长时接触区与反力变化的发展过程。 相似文献
573.
研究了非圆截面杆中非线性扭转波的传播特性.由于非圆截面杆的扭转运动会伴随有横截面的翘曲,这种翘曲运动将引起扭转波的弥散.如果同时考虑有限扭转变形和翘曲弥散的共同作用,将会得到非线性扭转波的方程.在相平面上,对非线性扭转波动方程进行定性分析,结果表明,在一定条件下方程存在同宿轨道或异宿轨道,分别相应于方程的孤波解或冲击波解.本文利用Jacobi椭圆函数展开法,对该非线性方程进行求解,得到了非线性波动方程的三类准确周期解及相应的孤波解和冲击波解,讨论了这些解存在的必要条件.这些条件与定性分析的结果相一致. 相似文献
574.
IntroductionThebehavioroflateral_torsionalcoupledbuildingintheinelasticrangehadbeenwidelyinvestigated.KanandChopra(1981)[1]studiedaone_storymodelwithsinglelateralresistantelementandreachedtheconclusionthatgenerallytheresponseintheinelasticrangeisaffectedb… 相似文献
575.
By coupling natural boundary element method (NBEM) with FEM based on domain decomposition, the torsion problem of the square
cross-sections bar with cracks have been studied, the stresses of the nodes of the cross-sections and the stress intensity
factors have been calculated, and some distribution pictures of the stresses have been drawn. During computing, the effect
of the relaxed factors to the convergence speed of the iterative method has been discussed. The results of the computation
have confirmed the advantages of the NBEM and its coupling with the FEM.
Foundation item: the State Key Laboratory of Science and Engineering Computation
Biography: ZHAO Hui-ming (1971-) 相似文献
576.
577.
In the present study, we are interested in finding the spin precession of a Dirac particle in expanding and rotating NUT spaeetime. A tetrad with two functions to be determined is applied to the field equation of the teleparallel theory of gravity via a coordinate transformation. The vector, the axial-vector and the tensor parts of the torsion tensor are obtained. We found that the vector parts are in the radial and Ф-directions. The axial-vector torsion is along r-direction while its other components along θ and oh-directions vanish everywhere. The vector connected with Dirac spin has been evaluated as well. 相似文献
578.
In this paper we classify cylindrically symmetric static space-timesaccording to their teleparallel homothetic vector fields using directintegration technique. It turns out that the dimensions of the teleparallelhomothetic vector fields are 4, 5, 7 or 11, which are the same in numbers asin general relativity. In case of 4, 5 or 7 proper teleparallel homotheticvector fields exist for the special choice to the space-times. In the caseof 11 teleparallel homothetic vector fields the space-time becomes Minkowskiwith all the zero torsion components. Teleparallel homothetic vector fieldsin this case are exactly the same as in general relativity. It is importantto note that this classification also covers the plane symmetric static space-times. 相似文献
579.
In this paper a general solution for the analysis of shear deformable stiffened plates subjected to arbitrary loading is presented.
According to the proposed model, the arbitrarily placed parallel stiffening beams of arbitrary doubly symmetric cross section
are isolated from the plate by sections in the lower outer surface of the plate, taking into account the arising tractions
in all directions at the fictitious interfaces. These tractions are integrated with respect to each half of the interface
width resulting two interface lines, along which the loading of the beams as well as the additional loading of the plate is
defined. Their unknown distribution is established by applying continuity conditions in all directions at the interfaces.
The utilization of two interface lines for each beam enables the nonuniform distribution of the interface transverse shear
forces and the nonuniform torsional response of the beams to be taken into account. The analysis of both the plate and the
beams is accomplished on their deformed shape taking into account second-order effects. The analysis of the plate is based
on Reissner’s theory, which may be considered as the standard thick plate theory with which all others are compared, while
the analysis of the beams is performed employing the linearized second order theory taking into account shear deformation
effect. Six boundary value problems are formulated and solved using the analog equation method (AEM), a BEM based method.
The solution of the aforementioned plate and beam problems, which are nonlinearly coupled, is achieved using iterative numerical
methods. The adopted model permits the evaluation of the shear forces at the interfaces in both directions, the knowledge
of which is very important in the design of prefabricated ribbed plates. The effectiveness, the range of applications of the
proposed method and the influence of shear deformation effect are illustrated by working out numerical examples with great
practical interest. 相似文献
580.
R. M. Lees Li-Hong Xu S. Twagirayezu D. S. Perry M. B. Dawadi B. E. Billinghurst 《Molecular physics》2018,116(23-24):3554-3563
ABSTRACTThe infrared Fourier transform spectrum of the S–H stretching fundamental band of 12CH3 32SH has been recorded using synchrotron radiation at the far-infrared beamline of the Canadian Light Source in Saskatoon. The S–H stretch is a hybrid band predominantly of perpendicular b-type with a small parallel a-component. With both ΔK = +1 and ΔK = ?1 sub-bands present, the assignments are well determined from ground-state combination difference relations. The identified sub-bands access S–H stretching ground torsional substates from K′ = 0–14 for A and E torsional species. The substate origins have been obtained by expanding the term values in J(J + 1) power series, and have been fitted to a simple 6-parameter Fourier Hamiltonian to deduce the torsional energies. The oscillation amplitude of the S–H stretching torsional curves is 0.547 cm? 1 compared to 0.653 cm? 1 for the ground state, implying an increase on the order of 6.9% in the torsional barrier height. The vibrational wavenumber for the S–H stretch mode is found to be 2603.5 cm? 1. 相似文献