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1.
In this paper,the Kane’s equations for the Routh’s form of variable massnonholonomic systems are established.and the Kane’s equations for percussion motionof variable mass holonomic and nonholonomic systems are deduced from them. Secondly,the equivalence to Lagrange’s equations for percussion motion and Kane’sequations is obtained,and the application of the new equation is illustrated by anexample.  相似文献   

2.
In this paper,the Gibbs-Appell’s equations of motion are extended to the most generalvariable mass nonholonomic mechanical systems.Then the Gibbs-Appell’s equations ofmotion in terms of generalized coordinates or quasi-coordinates and an integral variationalprinciple of variable mass nonlinear nonholonomic mechanical systems are obtained.Finally,an example is given.  相似文献   

3.
In this paper, a direct probabilistic approach (DPA) is presented to formulate and solve moment equations for nonlinear systems excited by environmental loads that can be either a stationary or nonstationary random process. The proposed method has the advantage of obtaining the response’s moments directly from the initial conditions and statistical characteristics of the corresponding external exci-tations. First, the response’s moment equations are directly derived based on a DPA, which is completely independent of the It?/filtering approach since no specific assumptions regarding the correlation structure of excitation are made. By solving them under Gaussian closure, the response’s moments can be obtained. Subsequently, a multiscale algo-rithm for the numerical solution of moment equations is exploited to improve computational efficiency and avoid much wall-clock time. Finally, a comparison of the results with Monte Carlo (MC) simulation gives good agreement. Furthermore, the advantage of the multiscale algorithm in terms of efficiency is also demonstrated by an engineering example.  相似文献   

4.
The paper establishes the universal D’Alembert’s principle in variable massmechanical system.Then derives the different kinds of the differential equations of variablemass in high-order non-holonomic mechanical system.Finally,the applications for example are illustrated by these mew equations.  相似文献   

5.
Originating from Robert Hooke’s law and equilibrious equations,and using the theoryof the complex variable function,this paper transfers the rectaugle region in which thecracks emerge into upper-half part of ξplane by means of conformal mapping.Thenaccording to the theory of ref.[1].We find the solution in closed form,thereby the stressintensity factors are derived.  相似文献   

6.
Lyapunov's first method, extended by V. V. Kozlov to nonlinear mechani- cal systems, is applied to the study of the instability of the position of equilibrium of a mechanical system moving in the field of conservative and dissipative forces. The mo- tion of the system is limited by ideal nonlinear nonholonomic constraints. Five cases determined by the relationship between the degree of the first nontrivial polynomials in Maclaurin's series for the potential energy and the functions that can be generated from the equations of nonlinear nonholonomic constraints are analyzed. In the three eases, the theorem on the instability of the position of equilibrium of nonholonomic systems with linear homogeneous constraints (V. V. Kozlov (1986)) is generalized to the case of nonlin- ear nonhomogeneous constraints. In the other two cases, new theorems are set extending the result from V. V. Kozlov (1994) to nonholonomic systems with nonlinear constraints.  相似文献   

7.
Originating from Robert Hooke’s law and equilibrious equations. and using the theory of the complex variable function, this paper transfers the rectaugle region in which the cracks emerge into upper-half part of ζplane by means of conformal mapping. Then according to the theory of ref.[1]. We find the solution in closed form. there by the stress intensity factors are derived.  相似文献   

8.
9.
In this paper, the definitions of Nielsen’s and Euler’s operators of higher order are presented. These operators are concerned in analysis for systems with holonomic constraints and non-holonomic constraints of higher order. Some theorems that indicating relation between the two operators are established. Moreover, using the theorems, the new equations of mechanical systems with constraints of higher order are derived. Finally, an example is given.  相似文献   

10.
An infinite system of two-dimensional equations of motion of isotropic elastic plates with edge and corner conditions are deduced from the three-dimensional equations of elasticity by expansion of displacements in a series of trigonometrical functions and a linear function of the thickness coordinate of the plate. The linear term in the expansion is to accommodate the in-plane displacements induced by the rotation of the plate normal in low-frequency flexural motions. A system of first-order equations of flexural motions and accompanying boundary conditions are extracted from the infinite system. It is shown that the present system of equations is equivalent to the Mindlin’s first-order equations, and the dispersion relation of straight-crested waves of the present theory is identical to that of the Mindlin’s without introducing any corrections. Reduction of present equations and boundary conditions to those of classical plate theories of flexural motions is also presented.  相似文献   

11.
A field method for solving the equations of motion of nonholonomic systems   总被引:6,自引:0,他引:6  
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   

12.
1.IntroductionMoreandmoreattentionhasbeenpaidtothestudyofdynamicsofcomplicatedsystemwiththedevelopmentofmodernscienceandtechnology.Thestudyoftherelativemotionofvariablemasssystembyusingthetheoryandmethodofanalyticalmechanicsnotonlycanunifytheexpressionformbutalsocandisplayitssuperioritytothecomplicatedsystem.In1961,thedynamicsofrelativemotionofholonomicsystemwasderivedbyLur'ell].Inrecehtyears,LiulZIandLuol3'4]havegiventhedynamicsequationsofrelativemotionofvariablemassnonholonomicsystem.Howe…  相似文献   

13.
In this paper, the Gibbs-Appell' s equations of the nonholonomic controllable mechanical systems with variable mass in terms of quasi-velocities and quasi-accelerations are obtained, and the application of the new equation is illustrated by an example.The project was Supported by the Heilongjiang Natural Science Foundation  相似文献   

14.
This paper presents the generalized principles of least action of variable massnonholonomic nonconservative system in noninertial reference frame, proves theequivalence between Holder form and Suslov form, and then obtains differential equationsof motion of variable mass nonholonomic nonconservative system in noninertial referenceframe.  相似文献   

15.
邹杰涛  吴润衡 《力学季刊》2001,22(3):369-373
研究非完整系统的Lie对称性与Noether对称性及其间的关系,具体研究了Chetaev型变量质量非完整系统和非Chetaev型非完整系统的Lie对称性与Noether对称性。给出Lie对称性导致Noether对称性及Noether对称性导致Lie对称性的条件。  相似文献   

16.
吴润衡  邹杰涛 《力学季刊》2000,21(3):331-336
本文研究质量非完整系统的Lie对称性逆问题:根据已知积分求相应的Lie对称性,具体研究了受Chetaev型和非Chetaev型非完整约束的变质量系统的Lie对称性逆问题。首先,根据Lie对称所满足的确定方程和限制方程,给出Lie对称的结构方程和相应的守恒量及其表达式;其次,由已知守恒量求出相应的Noether对称性;最后,根据Noether对称性求出相应的Lie对称性。  相似文献   

17.
变质量非完整系统相对运动动力学方程的积分理论   总被引:1,自引:0,他引:1  
本文研究变质量非线性非完整系统相对于非惯性系动力学的积分理论,给出其Routh降阶法,Whittaker降阶法,Poincare-Cartan型积分变量关系和积分不变量。  相似文献   

18.
力学的新型积分变分原理   总被引:3,自引:0,他引:3  
赵跃宇 《力学学报》1989,21(1):101-106
  相似文献   

19.
I.IntroductionTheinverseproblemofdynamicsisoneoftheimportantsubjectsinmechanics.In1977,Szebehelysetforthaninverseproblemforthedeterminationofthet'orcefunctiontoamaterialpointintheplanefromparametricfamilyoftrajectories,andobtainedalinearfirstorderpartialdifferentialequationfortheforcefunction.Later,Erdil'l,MellsandPirast=l,MellsandBorgherol'l,BoilsandMertnsl4]extendedSzebehely'sproblemtoboththreeandndimensionalholonomicsystem.Recently,theauthorandProfessorMetFengxiangl'1studiedtheSzebehe…  相似文献   

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