Fractional calculus is widely used to deal with nonconservative dynamics because of its memorability and non-local properties.In this paper,the Herglotz principle with generalized operators is discussed,and the Herglo...Fractional calculus is widely used to deal with nonconservative dynamics because of its memorability and non-local properties.In this paper,the Herglotz principle with generalized operators is discussed,and the Herglotz type equations for nonholonomic systems are established.Then,the Noether symmetries are studied,and the conserved quantities are obtained.The results are extended to nonholonomic canonical systems,and the Herglotz type canonical equations and the Noether theorems are obtained.Two examples are provided to demonstrate the validity of the methods and results.展开更多
自然界和工程技术领域存在大量的非线性问题,它们通常需要用非线性微分方程来描述.守恒量在微分方程的求解、约化和定性分析方面发挥重要作用.因此,研究非线性动力学方程的近似守恒量具有重要意义.文章利用Noether对称性方法研究弱非线...自然界和工程技术领域存在大量的非线性问题,它们通常需要用非线性微分方程来描述.守恒量在微分方程的求解、约化和定性分析方面发挥重要作用.因此,研究非线性动力学方程的近似守恒量具有重要意义.文章利用Noether对称性方法研究弱非线性动力学方程的近似守恒量.首先,将弱非线性动力学方程化为一般完整系统的Lagrange方程,在Lagrange框架下建立Noether准对称性的定义和广义Noether等式,给出近似Noether守恒量.其次,将弱非线性动力学方程化为相空间中一般完整系统的Hamilton方程,在Hamilton框架下建立Noether准对称性的定义和广义Noether等式,给出近似Noether守恒量.再次,将弱非线性动力学方程化为广义Birkhoff方程,在Birkhoff框架下建立Noether准对称性的定义和广义Noether等式,给出近似Noether守恒量.最后,以著名的van der Pol方程,Duffing方程以及弱非线性耦合振子为例,分析三个不同框架下弱非线性系统的Noether准对称性与近似Noether守恒量的计算.结果表明:同一弱非线性动力学方程可以化为不同的一般完整系统或不同的广义Birkhoff系统;Hamilton框架下的结果是Birkhoff框架的特例,而Lagrange框架下的结果与Hamilton框架的等价.利用Noether对称性方法寻找弱非线性动力学方程的近似守恒量不仅方便有效,而且具有较大的灵活性.展开更多
Noether symmetry of Nielsen equation and Noether conserved quantity deduced directly from Noether symmetry for dynamical systems of the relative motion are studied. The definition and criteria of Noether symmetry of a...Noether symmetry of Nielsen equation and Noether conserved quantity deduced directly from Noether symmetry for dynamical systems of the relative motion are studied. The definition and criteria of Noether symmetry of a Nielsen equation under the infinitesimal transformations of groups are given. Expression of Noether conserved quantity deduced directly from Noether symmetry of Nielsen equation for the system are obtained. Finally, an example is given to illustrate the application of the results.展开更多
A new kind of weak Noether symmetry for a general holonomic system is defined in such a way that themethods to construct Hojman conserved quantity and new-type conserved quantity are given.It turns out that weintroduc...A new kind of weak Noether symmetry for a general holonomic system is defined in such a way that themethods to construct Hojman conserved quantity and new-type conserved quantity are given.It turns out that weintroduce a new approach to look for the conserved laws.Two examples are presented.展开更多
In this paper,the Noether Lie symmetry and conserved quantities of generalized classical mechanical system are studied.The definition and the criterion of the Noether Lie symmetry for the system under the general infi...In this paper,the Noether Lie symmetry and conserved quantities of generalized classical mechanical system are studied.The definition and the criterion of the Noether Lie symmetry for the system under the general infinitesimal transformations of groups are given.The Noether conserved quantity and the Hojman conserved quantity deduced from the Noether Lie symmetry are obtained.An example is given to illustrate the application of the results.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12272248)the Postgraduate Research and Practice Innovation Program of Jiangsu Province of China(Grant No.KYCX23_3296).
摘要Fractional calculus is widely used to deal with nonconservative dynamics because of its memorability and non-local properties.In this paper,the Herglotz principle with generalized operators is discussed,and the Herglotz type equations for nonholonomic systems are established.Then,the Noether symmetries are studied,and the conserved quantities are obtained.The results are extended to nonholonomic canonical systems,and the Herglotz type canonical equations and the Noether theorems are obtained.Two examples are provided to demonstrate the validity of the methods and results.
摘要自然界和工程技术领域存在大量的非线性问题,它们通常需要用非线性微分方程来描述.守恒量在微分方程的求解、约化和定性分析方面发挥重要作用.因此,研究非线性动力学方程的近似守恒量具有重要意义.文章利用Noether对称性方法研究弱非线性动力学方程的近似守恒量.首先,将弱非线性动力学方程化为一般完整系统的Lagrange方程,在Lagrange框架下建立Noether准对称性的定义和广义Noether等式,给出近似Noether守恒量.其次,将弱非线性动力学方程化为相空间中一般完整系统的Hamilton方程,在Hamilton框架下建立Noether准对称性的定义和广义Noether等式,给出近似Noether守恒量.再次,将弱非线性动力学方程化为广义Birkhoff方程,在Birkhoff框架下建立Noether准对称性的定义和广义Noether等式,给出近似Noether守恒量.最后,以著名的van der Pol方程,Duffing方程以及弱非线性耦合振子为例,分析三个不同框架下弱非线性系统的Noether准对称性与近似Noether守恒量的计算.结果表明:同一弱非线性动力学方程可以化为不同的一般完整系统或不同的广义Birkhoff系统;Hamilton框架下的结果是Birkhoff框架的特例,而Lagrange框架下的结果与Hamilton框架的等价.利用Noether对称性方法寻找弱非线性动力学方程的近似守恒量不仅方便有效,而且具有较大的灵活性.
基金Supported by the National Natural Science Foundation of China under Grant No.10572021the Preparatory Research Foundation of Jiangnan University under Grant No.2008LYY011
摘要Noether symmetry of Nielsen equation and Noether conserved quantity deduced directly from Noether symmetry for dynamical systems of the relative motion are studied. The definition and criteria of Noether symmetry of a Nielsen equation under the infinitesimal transformations of groups are given. Expression of Noether conserved quantity deduced directly from Noether symmetry of Nielsen equation for the system are obtained. Finally, an example is given to illustrate the application of the results.
基金National Natural Science Foundation of China under Grant Nos.10572021 and 10772025the Doctoral Programme Foundation of the Institute of Higher Education of China under Grant No.20040007022
摘要A new kind of weak Noether symmetry for a general holonomic system is defined in such a way that themethods to construct Hojman conserved quantity and new-type conserved quantity are given.It turns out that weintroduce a new approach to look for the conserved laws.Two examples are presented.
摘要In this paper,the Noether Lie symmetry and conserved quantities of generalized classical mechanical system are studied.The definition and the criterion of the Noether Lie symmetry for the system under the general infinitesimal transformations of groups are given.The Noether conserved quantity and the Hojman conserved quantity deduced from the Noether Lie symmetry are obtained.An example is given to illustrate the application of the results.