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Transfer matrix method for multibody systems(Rui method) and its applications

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Science China(Technological Sciences) 2019年第5期62卷 712-720页

作者： RUI XiaoTing WANG Xun ZHOU QinBo ZHANG JianShu Institute of launch Dynamics Nanjing University of Science and Technology

The transfer matrix method for multibody systems, namely the "Rui method", is a new method for studying multibody system dynamics, which avoids the global dynamics equations of the system, keeps high computational speed, and allows highly formalized programming. It has been widely applied to scientific research and key engineering of lots of complex mechanical systems in 52 research directions. The following aspects regarding the transfer matrix method for multibody systems are reviewed systematically in this paper: history, basic principles, formulas, algorithm, automatic deduction theorem of overall transfer equation, visualized simulation and design software, highlights, tendency, and applications in 52 research directions in over 100 key engineering products.

关键词： multibody system dynamics transfer matrix method for multibody systems Rui method automatic deduction theorem of overall transfer equation theory computation software applications

Optimal design of 6-DOF vibration isolation platform based on transfer matrix method for multibody systems

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Acta Mechanica Sinica 2021年第1期37卷 127-137,I0004页

作者： Min Jiang Xiaoting Rui Wei Zhu Fufeng Yang Yanni Zhang Institute of launch Dynamics Nanjing University of Science and TechnologyNanjing210094China

The structure parameters of 6-degree of freedom(DOF)vibration isolation platform have a significant effect on its *** make the designed vibration isolation platform perform well,non-dominanted sorting genetic algorithm version II(NSGA-II)was applied to optimize its structure based on the transfer matrix method for multibody ***,the Jacobian matrix of 6-DOF vibration isolation platform was solved based on ***,the transfer equation of 6-DOF vibration isolation system was established by the linear transfer matrix method for multibody *** the formula of its natural frequency was derived according to the boundary conditions of the ***,the manipulability index was constructed based on a dimensionless Jacobian *** a new performance index function was established considering the influence of dynamic isotropic and legs ***,genetic algorithm(GA)and NSGA-II were used to optimize the structure of the 6-DOF vibration isolation platform under the same conditions,*** showed that NSGA-II had higher optimization efficiency,better calculation accuracy and shorter optimization time than that of ***,NSGA-II was adopted for multi-objective optimization design of 6-DOF vibration isolation platform based on the constraint *** Pareto solutions were obtained,which provides structural parameters for subsequent design ***,the proposed optimization method and the performance index in this paper provide a theoretical basis for the optimal design of relevant vibration isolation mechanism.

关键词： Optimal design 6-DOF vibration isolation Transfer matrix method Non-dominanted sorting genetic algorithm version II(NSGA-II)

Exploring practical methods for detecting k-nonseparability in multipartite quantum states

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 255-256页

作者： Shunlong Luo Academy of Mathematics and systems Science Chinese Academy of Sciences

Quantum entanglement, referred to as “spooky action at a distance” by Einstein, is not only an intriguing and fascinating feature of quantum theory challenging our classical intuitions about locality and correlations, but also has practical and profound implications for quantum technologies. Initially described by Einstein, Podolsky and Rosen, as well as by Schro¨dinger, entanglement now has become a basic and crucial ingredient for both foundational and experimental investigations of the quantum world.

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Discrete time transfer matrix method for dynamics analysis of complex weapon systems

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Science China(Technological Sciences) 2011年第5期54卷 1061-1071页

作者： RUI XiaoTing RONG Bao WANG GuoPing HE Bin Institute of launch Dynamics Nanjing University of Science and Technology Nanjing 210094 China

Efficient, precise dynamic modeling and analysis for complex weapon systems have become more and more important in their dynamic design and performance optimizing. As a new method developed in recent years, the discrete time transfer matrix method of multibody system is highly efficient for multibody system dynamics. In this paper, taking a shipboard gun system as an example, by deducing some new transfer equations of elements, the discrete time transfer matrix method of multibody sys- tem is used to solve the dynamics problems of complex rigid-flexible coupling weapon systems successfully. This method does not need the global dynamic equations of system and has the low order of system matrix, high computational efficiency. The proposed method has advantages for dynamic design of complex weapon systems, and can be carried over straightforwardly to other complex mechanical systems.

关键词： multibody system dynamics transfer matrix method shipboard gun finite element

A novel method of Newton iteration-based interval analysis for multidisciplinary systems

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Science China(Physics,Mechanics & Astronomy) 2017年第9期60卷 47-62页

作者： Lei Wang Chuang Xiong RuiXing Wang XiaoJun Wang Di Wu Institute of Solid Mechanics Beihang University China Academy of launch Vehicle Technology R&D Center

A Newton iteration-based interval uncertainty analysis method(NI-IUAM) is proposed to analyze the propagating effect of interval uncertainty in multidisciplinary systems. NI-IUAM decomposes one multidisciplinary system into single disciplines and utilizes a Newton iteration equation to obtain the upper and lower bounds of coupled state variables at each iterative ***-IUAM only needs to determine the bounds of uncertain parameters and does not require specific distribution formats. In this way, NI-IUAM may greatly reduce the necessity for raw data. In addition, NI-IUAM can accelerate the convergence process as a result of the super-linear convergence of Newton iteration. The applicability of the proposed method is discussed, in particular that solutions obtained in each discipline must be compatible in multidisciplinary systems. The validity and efficiency of NI-IUAM is demonstrated by both numerical and engineering examples.

关键词： multidisciplinary systems uncertainty propagation insufficient sample data interval uncertainty analysis method Newton iteration

Global cavitation and hydrodynamic characteristics of a composite propeller in non-uniform wake

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Journal of Hydrodynamics 2023年第3期35卷 498-515页

作者： Dan-dan Zhang Lu-lu Dong Qin Wu Jing Zhang Guo-yu Wang School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China China Academy of launch Vehicle Technology systems Engineering Division Beijing 100076China

The composite propeller has attracted much interest due to its excellent mechanical properties such as high specific stiffness and high specific strength,hence there is an increasing interest in utilizing the composite materials to improve the hydrodynamic and structural performance of marine *** objective of this paper is to study the cavitation performance of composite propellers based on the unsteady simulation method considering the cavitation-composite structure *** typical cavitation patterns around the composite propeller are studied,which include blade sheet cavitation and tip vortex *** unsteady flow characteristics of tip vortex cavitation and structural dynamic response of composite propeller are studied,and the mechanism of composite propeller for the cavitation suppression and efficiency improvement is *** results show that compared with rigid propellers,composite propellers have smaller cavity volume and higher propulsion efficiency under the same *** unsteady cavitating flow characteristics under non-uniform wake are periodic,and the phase lag of hydrodynamic coefficients of composite propeller can be observed compared with that of the rigid *** bending-torsional coupling deformation of the composite propeller makes the pressure pulsation of the flow field gentler,which reduces the influence of the cavitation load on the composite propeller.

关键词： Composite propeller unsteady cavitation hydrodynamic characteristics fluid-structure interaction(FSI)

Transfer matrix method for determination of the natural vibration characteristics of elastically coupled launch vehicle boosters

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Acta Mechanica Sinica 2015年第4期31卷 570-580页

作者： Laith K.Abbas Qinbo Zhou Hossam Hendy Xiaoting Rui Institute of launch Dynamics Nanjing University of Science and Technology

The analysis of natural vibration characteristics has become one of important steps of the manufacture and dynamic design in the aerospace industry. This paper presents a new scenario called virtual cutting in the context of the transfer matrix method of linear multibody systems closed- loop topology for computing the free vibration characteristics of elastically coupled flexible launch vehicle boosters. In this approach, the coupled system is idealized as a triple-beam system-like structure coupled by linear translational springs, where a non-uniform free-free Euler-Bemoulli beam is used. A large thrust-to-weight ratio leads to large axial accelera- tions that result in an axial inertia load distribution from nose to tail. Consequently, it causes the development of significant compressive forces along the length of the launch vehicle. Therefore, it is important to take into account this effect in the transverse vibration model. This scenario does not need the global dynamics equations of a system, and it has high computational efficiency and low memory requirements. The validity of the presented scenario is achieved through com- parison to other approaches published in the literature.

关键词： Transfer matrix method of linear multibodysystems Free vibration characteristics Coupled launchvehicle boosters

System-Level EMC Assessment for Military Vehicular Communication systems Based on a Modified Four-Level Assessment Model

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China Communications 2018年第8期15卷 39-53页

作者： Ping Zhou Yinghua Lv Zhihong Chen Hongping Xu School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing Institute of Astronautic System Engineering China Academy of Launch Vehicle Technology

With the development of EMC technology, EMC assessment has become increasingly important in EMC design. Although numerous EMC assessment models are available today, few of them can provide a tradeoff between efficiency and accuracy for the specific case of military vehicular communication systems. Face to this situation, a modified four-level assessment model is proposed in the paper. First, the development of EMC assessment technology is briefly reviewed, and the theoretical mechanism of EMI environment is introduced. Then, the architecture of the proposed model is outlined, and the assessment methods are explored. To demonstrate the application of it, an example involving a communication system in a military vehicle is presented. From the physical layer to the signal layer, a hierarchical assessment on the entire system is successfully performed based on the proposed model, and we can make a qualitative EMC assessment on the EMC performance of the system. Based on a comparison with the traditional model, we conclude that the proposed model is more accurate, more efficient and less time-consuming, which is suitable for the EMC assessment on militaryvehicular communication systems. We hope that the proposed model will serve as a useful reference for system-level EMC assessments for other systems.

关键词： military vehicular communication system system-level electromagnetic compatibility (EMC) assessment four-level assessment model

NONPARAMETRIC APPROACH TO IDENTIFYING NARX systems

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Journal of systems Science & Complexity 2010年第1期23卷 3-21页

作者： Qijiang SONG·Han-Pu CHEN Key Laboratory of systems and Control,Institute of systems Science,Academy of Mathematics and systems Science,Chinese Academy of Sciences,Beijing 100190,China Key Laboratory of systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences

This paper considers identification of the nonlinear autoregression with exogenous inputs(NARX system).The growth rate of the nonlinear function is required be not faster than linear withslope less than *** value of f(·) at any fixed point is recursively estimated by the stochasticapproximation (SA) algorithm with the help of kernel *** consistency of the estimatesis established under reasonable conditions,which,in particular,imply stability of the *** simulation is consistent with the theoretical analysis.

关键词： α-mixing geometrically ergodic Markov chains NARX nonparametric recursive estimate stochastic approximation strongly consistent.