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91.
QIAOYong-Fen LIRen-Jie MAYong-Sheng 《理论物理通讯》2004,42(6):801-804
Using the Lie Symmetry under infinitesimal transformations in which the time is not variable, the nonNoether conserved quantity of nonholonomic system having variable mass and unilateral constraints is studied. The differential equations of motion of the system are given. The determining equations of Lie symmetrical transformations of the system under infinitesimal transformations are constructed. The Hojman‘s conservation theorem of the system is established. Finally, we give an example to illustrate the application of the result. 相似文献
92.
A new conserved quantity of mechanical systems with differential constraints 总被引:1,自引:0,他引:1 下载免费PDF全文
A new conserved quantity of non-Noether symmetry for the mechanical systems with differential constraints is studied. First, the differential equations of motion of the systems are established. Then, the determining equations and restriction equations of the non-Noether symmetry are obtained and a new conserved quantity is given. Finally, an example is given to illustrate the application of the results. 相似文献
93.
含约束非线性动力系统的分岔分类 总被引:3,自引:3,他引:0
讨论含约束非线性动力系统分岔的分类.研究表明,约束分岔的转迁集,除分岔集、滞后集和双极限点集外,还有三种转迁集是它特有的.在此基础上提出了一种约束分岔问题的奇异性分类方法. 相似文献
94.
一族Liouville可积系及其约束流的Lax表示、Darboux变换 总被引:2,自引:0,他引:2
利用屠规彰格式求出了一族Liouville可积系,通过高阶位势特征函数约束将可积系分解成x部分和tn部分可积Hamilton系统,求出了该系统的Lax表示及三类Darboux变换。 相似文献
95.
96.
Xiaoqing Jin Leon M. Keer Kraiwood Kiattikomol 《Journal of the mechanics and physics of solids》2008,56(4):1127-1146
The refined Dugdale-type plastic zones ahead of an external circular crack, subjected to a uniform displacement at infinity, are evaluated both analytically and numerically. The analytical method utilizes potential theory in classical linear elasticity with emphasis on the contrast from the internal crack problem. A closed-form solution to the mixed boundary problem is obtained to predict the length of the plastic zone for a Tresca yield condition. The analytical solution is also used to benchmark the results obtained from the numerical method, which show good agreement. Through an iterative scheme, the numerical technique is able to estimate the size of crack tip plasticity zone, which is governed by the non-linear von Mises criterion. The relationships between the applied displacement and the length of the plastic zone are compared for the different yielding conditions. Computational modeling has demonstrated that the plastic constraint effect based on the true yield condition can significantly influence the load-bearing capacity. It is also discovered from the comparative study that the stress components predicted by the three different yield conditions may differ notably; however, the stress triaxiality in the ligament region has only small deviations. The proposed study may find applications in predicting the plastic flow in a circumferentially notched round bars under tension. 相似文献
97.
For stochastic control problems with mixed state-control constraints, we develop a dynamics aggregation method which replaces the stochastic differential or difference equation with a simpler constraint. Solutions of such simplified problems are used to construct a sequence of approximations to the original problem. Convergence properties of the method for both discrete-time and continuous-time models are analyzed in detail. 相似文献
98.
Boris Kruglikov 《Acta Appl Math》2008,101(1-3):145-161
Many methods for reducing and simplifying differential equations are known. They provide various generalizations of the original
symmetry approach of Sophus Lie. Plenty of relations between them have been noticed and in this note a unifying approach will
be discussed. It is rather close to the differential constraint method, but we make this rigorous basing on recent advances
in compatibility theory of non-linear overdetermined systems and homological methods for PDEs.
相似文献
99.
On-line scheduling with non-crossing constraints 总被引:1,自引:0,他引:1
We consider the problem of on-line scheduling with non-crossing constraints. The objective is to minimize the latest completion time. We provide optimal competitive ratio heuristics for the on-line list and on-line time problems with unit processing times, and a 3-competitive heuristic for the general on-line time problem. 相似文献
100.
Radu Ioan Bo? Sorin-Mihai Grad 《Journal of Mathematical Analysis and Applications》2008,337(2):1315-1325
We give some necessary and sufficient conditions which completely characterize the strong and total Lagrange duality, respectively, for convex optimization problems in separated locally convex spaces. We also prove similar statements for the problems obtained by perturbing the objective functions of the primal problems by arbitrary linear functionals. In the particular case when we deal with convex optimization problems having infinitely many convex inequalities as constraints the conditions we work with turn into the so-called Farkas-Minkowski and locally Farkas-Minkowski conditions for systems of convex inequalities, recently used in the literature. Moreover, we show that our new results extend some existing ones in the literature. 相似文献