By use of the recursive formulation of flexible multibody system with closed loops,this paper studies the dynamic simulation of complicated multibody system.The conception of static correction modes in structural dyna...By use of the recursive formulation of flexible multibody system with closed loops,this paper studies the dynamic simulation of complicated multibody system.The conception of static correction modes in structural dynamics is introduced to present the local deformation effects due to reaction forces at kinematic joints.A space four bar mechanism is utilized here as an example to describe the method of selecting static correction modes.Compared with vibration normal modes, static correction modes are demonstrated to be effective in numerical simulation.展开更多
In this paper, a new semi-analytical and semi-engineering method of the closed form solution of stress intensity factors （SIFs） of cracks emanating from a surface semi-spherical cavity in a finite body is derived us...In this paper, a new semi-analytical and semi-engineering method of the closed form solution of stress intensity factors （SIFs） of cracks emanating from a surface semi-spherical cavity in a finite body is derived using the energy release rate theory. A mode of crack opening displacements of a normal slice is established, and the normal slice relevant functions are introduced. The proposed method is both effective and accurate for the problem of three-dimensional cracks emanating from a surface cavity. A series of useful results of SIFs are obtained.展开更多
We establish the links between the lightlike geometry and basics invariants of the associated semi-Riemannian geometry on r-lightlike submanifold and semi-Riemannian constructed from a semi-Riemannian ambient. Then we...We establish the links between the lightlike geometry and basics invariants of the associated semi-Riemannian geometry on r-lightlike submanifold and semi-Riemannian constructed from a semi-Riemannian ambient. Then we establish some basic inequalities, involving the scalar curvature and shape operator on r-lightlike coisotropic submanifold in semi-Riemannian manifold. Equality cases are also discussed.展开更多
By using Artin-Wedderburn Theorem and the decomp- osition of central edepotent, several results about normality on closed subsets in standard table algebras are generalized to complex semi-simple algebras and the proo...By using Artin-Wedderburn Theorem and the decomp- osition of central edepotent, several results about normality on closed subsets in standard table algebras are generalized to complex semi-simple algebras and the proofs are easier than the original ones.展开更多
双电源配电环网是实现配电网故障无缝自愈、有效解决短时停电问题的基础,但配电环网中潮流呈自然分布,且缺乏有效的调节手段,统一潮流控制器(unified power flowcontroller,UPFC)可对环网潮流进行控制,但需突破其经济性瓶颈。为此,在调...双电源配电环网是实现配电网故障无缝自愈、有效解决短时停电问题的基础,但配电环网中潮流呈自然分布,且缺乏有效的调节手段,统一潮流控制器(unified power flowcontroller,UPFC)可对环网潮流进行控制,但需突破其经济性瓶颈。为此,在调节功率一定时,以负荷节点电压与环网两端馈线出力极限为约束条件,分别以UPFC输出的有功功率和视在功率最小为目标,提出了潮流控制策略。仿真结果表明2种优化控制策略能够满足配电环网潮流调度要求,且兼顾了UPFC应用的经济性。展开更多
文摘By use of the recursive formulation of flexible multibody system with closed loops,this paper studies the dynamic simulation of complicated multibody system.The conception of static correction modes in structural dynamics is introduced to present the local deformation effects due to reaction forces at kinematic joints.A space four bar mechanism is utilized here as an example to describe the method of selecting static correction modes.Compared with vibration normal modes, static correction modes are demonstrated to be effective in numerical simulation.
文摘In this paper, a new semi-analytical and semi-engineering method of the closed form solution of stress intensity factors （SIFs） of cracks emanating from a surface semi-spherical cavity in a finite body is derived using the energy release rate theory. A mode of crack opening displacements of a normal slice is established, and the normal slice relevant functions are introduced. The proposed method is both effective and accurate for the problem of three-dimensional cracks emanating from a surface cavity. A series of useful results of SIFs are obtained.
文摘We establish the links between the lightlike geometry and basics invariants of the associated semi-Riemannian geometry on r-lightlike submanifold and semi-Riemannian constructed from a semi-Riemannian ambient. Then we establish some basic inequalities, involving the scalar curvature and shape operator on r-lightlike coisotropic submanifold in semi-Riemannian manifold. Equality cases are also discussed.
基金Supported by the National Natural Science Foundation of China(11571129)Educational Commission of Hubei Province(D20132804)
文摘By using Artin-Wedderburn Theorem and the decomp- osition of central edepotent, several results about normality on closed subsets in standard table algebras are generalized to complex semi-simple algebras and the proofs are easier than the original ones.
文摘双电源配电环网是实现配电网故障无缝自愈、有效解决短时停电问题的基础,但配电环网中潮流呈自然分布,且缺乏有效的调节手段,统一潮流控制器(unified power flowcontroller,UPFC)可对环网潮流进行控制,但需突破其经济性瓶颈。为此,在调节功率一定时,以负荷节点电压与环网两端馈线出力极限为约束条件,分别以UPFC输出的有功功率和视在功率最小为目标,提出了潮流控制策略。仿真结果表明2种优化控制策略能够满足配电环网潮流调度要求,且兼顾了UPFC应用的经济性。
