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61.
用Trefftz型边界解法分析了中厚板弯曲问题,发现了一类新的、因Trefftz函数溢机引起的“自锁现象”,并提出了一种消除这类自锁问题的“变量减缩法”。 相似文献
62.
Mei Fengxiang 《Acta Mechanica Sinica》1989,5(3):260-268
In this paper, the field method[1] for solving the equations of motion of holonomic nonconservative systems is extended to nonholonomic systems with constant
mass and with variable mass. Two examples are given to illustrate its application.
The project supported by the National Natural Science Foundation of China. 相似文献
63.
S. D. Algazin 《Journal of Applied Mechanics and Technical Physics》2006,47(4):573-581
The problem of free vibrations of a beam with free ends of variable cross section and mass, from which point masses (oscillators)
are suspended by bars, is considered. It is shown that parametric resonances can occur in this oscillating system. Numerical
examples showing the efficiency of the calculation method proposed are given.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 135–144, July–August, 2006. 相似文献
64.
The topological optimization for truss structures with stress constraints based on the exist-null combined model 总被引:7,自引:0,他引:7
A new exist-null combined model is proposed for the structural topology optimization. The model is applied to the topology
optimization of the truss with stress constraints. Satisfactory computational result can be obtained with more rapid and more
stable convergence as compared with the cross-sectional optimization. This work also shows that the presence of independent
and continuous topological variable motivates the research of structural topology optimization.
The project supported by the State Key Laboratory for Structural Analysis of Industrial Equipment, Dalian University of Technology. 相似文献
65.
本文采用一种精确、简便的数值计算方法——微分求积单元法(DQEM)对变截面门式刚架结构进行了力学分析。首先建立了一般荷载作用下变截面构件的平衡微分方程,并采用微分求积法进行离散,进而得出了较为精确的分析变截面构件的单元力学模型。该模型的刚度方程不仅反映了单元的刚度性质,而且反映了单元的实际荷载作用,可较为精确地分析变截面门式刚架结构在分布载荷作用下的受力性能。通过与有限元法计算结果的比较,表明了微分求积单元法在变截面刚架的力学分析中的正确性和优越性。微分求积单元法可用于任意形状的刚架结构的静力分析。 相似文献
66.
本文研究了一种多变量在线测录仪,可用其在定向运转和反复正反变向运转的摩擦学试验中连续测量和记录试样的角速度、方位角、转数和摩擦距离等多个旋转变量的瞬时值,并且通过时间变量的关系,还可以清晰地显示出它们的变化过程和相互关系,基本能够描绘出试样在整个摩擦试验过程中的旋转动态。文章指出,利用这种测录仪还可得出一些间接的信息,如摩擦副的相对滑动量和试验过程中试样摩擦力的变化等。该仪器具有一机多用、所占空间 相似文献
67.
The incorporation of energy elastic effects in the modeling of flowing polymeric liquids is discussed. Since conformational
energetic effects are determined by structural features much smaller than the end-to-end vector of the polymer chains, commonly
employed single conformation tensor models are insufficient to describe energy elastic effects. The need for a local structural
variable is substantiated by studying a microscopic toy model with energetic effects in the setting of a generalized canonical
ensemble. In order to examine the dynamics of flowing polymeric liquids with energy elastic effects, a thermodynamically admissible
set of evolution equations is presented that accounts for the evolution of the microstructure in terms of a slow tensor, as
well as a fast, local scalar variable. It is demonstrated that the temperature used in the definition of the heat flux is
directly related to the Lagrange multiplier of the microscopic energy in the generalized canonical partition function. The
temperature equation is discussed with respect to, first, the dependence of the heat capacity on the polymer conformation
and, second, the possibility to measure experimentally the effects of the conformational energy.
相似文献
Markus HütterEmail: |
68.
INTEGRATION METHOD FOR THE DYNAMICS EQUATION OF RELATIVE MOTION OF VARIABLE MASS NONLINEAR NONHOLONOMIC SYSTEM 总被引:1,自引:0,他引:1
1.IntroductionMoreandmoreattentionhasbeenpaidtothestudyofdynamicsofcomplicatedsystemwiththedevelopmentofmodernscienceandtechnology.Thestudyoftherelativemotionofvariablemasssystembyusingthetheoryandmethodofanalyticalmechanicsnotonlycanunifytheexpressionformbutalsocandisplayitssuperioritytothecomplicatedsystem.In1961,thedynamicsofrelativemotionofholonomicsystemwasderivedbyLur'ell].Inrecehtyears,LiulZIandLuol3'4]havegiventhedynamicsequationsofrelativemotionofvariablemassnonholonomicsystem.Howe… 相似文献
69.
G.?JourdanEmail author L.?Houas L.?Schwaederlé G.?Layes R.?Carrey F.?Diaz 《Shock Waves》2004,13(6):501-504
A new variable inclination shock tube has been set up especially for the visualization of shock induced high speed flows. This device allows for the generation of shock waves of Mach numbers ranging from 1.05 to 4, moving horizontally, vertically from up to down or the opposite, or with any inclination angle. It is coupled with a suitable high-speed camera shadowgraph visualization system, and the whole facility has been realized so as to be both very easy to use and movable. We believe this example could be of interest to scientists interested in starting experiments on shock wave induced multi-phase complex flows. 相似文献
70.
IntroductionThestudyofsymmetryandconservedquantityofmechanicalsystemisanimportanttopicinmathematics,mechanicsandphysics .ThemoderntheoriesofsymmetryandconservedquantityofmechanicalsystemincludeNoethersymmetrytheoryandLiesymmetrytheory .In 1979M .Lutzkyando… 相似文献