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  • 1  Generalized mul ti-symplectic method for vibration of big damping bar
    Hu Weipeng Deng Zichen
    2013, 11(1):1-4. DOI: 10.6052/1672-6553-2013-001
    [Abstract](3687) [HTML](0) [PDF 294.91 K](2391)
    This paper studies the damping vibration properties of the big damping bar by the generalized multisymplectic method based on the Bridges’s multisymplectic method and the Hamilton variation principle. Introducing orthogonal momenta, a firstorder approximate symplectic form, named generalized multisymplectic form is derived from the control equation of the big damping bar vibration firstly. And then a midpoint Box generalized multisymplectic scheme is constructed by the midpoint method; Finally, the dissipation effect of the big damping bar vibration is studied. From the results of the numerical experiment, the good properties of the generalized multisymplectic method are verified: satisfying the conservative properties of the system and reproducing the dissipation effect of the system.
    2  The analogy method to coupling analysis of rockets considering propellant sloshing
    Zhu Changfan Tang Guoan Zhang Meiyan
    2014, 12(3):239-242. DOI: 10.6052/1672-6553-2014-044
    [Abstract](3076) [HTML](0) [PDF 386.27 K](2229)
    For the linear coupling of the elastic tank and incompressible and invisid liquid, there are reduced and symmetric finite element equations of coupling system. The system matrix could be obtained by the analogy method, and then the analysis of coupling system will turn to be a problem that could be solved by the general finite element software. For example, the modal characteristics of the rocket with tanks were studied. Coupling modes caused by liquid sloshing were founded, and the result shows the modes of this kind are relevant to the gravity acceleration. In addition, the greater the gravity, the higher the frequency.
    3  An automatic identification method for longitudinal modes of structural system of rocket
    Fang Bo Tang Ye Yang Feihu Zhang Yewei Zang Jian
    2014, 12(3):269-273. DOI: 10.6052/1672-6553-2014-043
    [Abstract](2991) [HTML](0) [PDF 336.30 K](4506)
    Aiming at the problem that the longitudinal modes of structural system of rocket need to be identified from its integral modes in engineering, a method that automatically identifies the longitudinal modes of structural system of rocket was proposed according to the theory of modal effective mass. Taking the vibration characteristics of system with lumped mass as a computing example, applying the finite element software, the beam model of system with lumped mass was established, and the longitudinal modes of the system were automatically identified based on the method. Compared with the system modal information calculated by the method of modal analysis, this automatic identification method not only can accurately identify the longitudinal modes of vibrating system, but also has automatic and high efficiency identification feature. It provides a theoretical basis for the dynamic model of POGO vibrating system in liquid rockets and other model of engineering systems to be accurately and promptly established.
    4  A new method on flutter tailoring techniques of high-aspect-ratio wings
    Ren Zhiyi Jin Haibo Ding Yuliang
    2014, 12(3):283-288. DOI: 10.6052/1672-6553-2014-061
    [Abstract](2701) [HTML](0) [PDF 479.50 K](3793)
    A method was presented to analyze the nonlinear flutter. Based on this method, the flutter characteristics of the high aspect wing were illustrated. The numerical results show that the flutter speed is decreased when the first horizontal bending mode involved. Secondly, this study discussed how the main direction of the composite influenced the character of the nonlinear vibration and flutter, and established the method of the flutter clipping to the high aspect wing. And the result shows that the stiffness of structure can be changed by changing the main direction of the composite. It mainly changes the horizontal bending mode, makes the main direction tend to the trailing edge, and then makes the section line move to the leading edge. Further analyzing the nonlinear flutter reveals that it is the changing of the horizontal bending mode that causes the flutter speed change obviously. And by the section line of this mode moves ahead, the flutter speed will become larger. In the study, two examples were illustrated to validate its truthiness.
    5  Progress in spacecraft vibration testing control technology
    Ci Yongwei Qiu Dalu Fu Leping Shao Xiaoping
    2014, 12(3):193-200. DOI: 10.6052/1672-6553-2014-046
    [Abstract](2690) [HTML](0) [PDF 748.46 K](5556)
    The spacecraft's ability to adapt to the harsh dynamics environment is critical for the whole space mission. Vibration test control technology is the key part of the dynamic environment test. The current progress, fundamental principles and key techniques development level of the spacecraft and vibration control algorithms overseas were analyzed. The basic ideas, effective ways and suggestions were given to domestic following research.
    6  Nonlinear modeling and analysis of piezoelectic cantilever energy harvester
    Guo Kangkang Cao Shuqian
    2014, 12(1):18-23. DOI: 10.6052/1672-6553-2013-068
    [Abstract](2632) [HTML](0) [PDF 1.13 M](5276)
    The electromechanical coupling model of cantilevered piezoelectric harvester was developed by considering the nonlinearities of piezoelectric material, based on Hamilton theory, Rayleigh-Ritz method, Euler-Bernoulli beam theory and constant electrical field across the piezoelectric element. The response characteristics of the system were investigated numerically, and the influences of piezoelectric material nonlinear coefficient on the system response were analyzed. By exploring the nonlinear characteristics of the piezoelectric vibrator near the resonant frequency, the nature of the multi-solutions and jump phenomena in the resonance region was revealed. The results were verified experimentally. which provides a theoretical basis for the study of nonlinear mechanism of piezoelectric power generation system.
    7  Analysis in the windage of asd outside the frequency bandwidth in random vibration testing
    Qiu Dalu Ci Yongwei Shao Xiaoping Fu Leping
    2014, 12(3):243-247. DOI: 10.6052/1672-6553-2014-054
    [Abstract](2356) [HTML](0) [PDF 1.07 M](4926)
    Random vibration test is very important to the aerospace equipment. The windage of ASD outside the frequency bandwidth was analyzed. The reason, premonition, affection and effective way were given. And the commonly used random vibration test and vibration test metrology standard for the ASD outside the frequency bandwidth were analyzed.
    8  Simulation of 'tail-slap' phenomenon of supercavitating projectiles with fluid/structure interaction
    He Qiankun Wang Cong Wei Yingjie
    2014, 12(3):225-229. DOI: 10.6052/1672-6553-2014-051
    [Abstract](2142) [HTML](0) [PDF 1.38 M](4558)
    Based on the staggered solution procedure of ANSYS and CFX software, the fluid structure coupling response of projectile during tail slapping has been researched. Structural response was simulated by using FEM and flow field was simulated by using inhomogeneous model and SST turbulence model. Finally, the influences of fluid structure coupling effect have been analyzed and the change law of body stress has been given.
    9  Nonlinear dynamic characteristics analysis of the gas exciting force in the rotor-seal system
    Li Zhonggang Chen Yushu Chen zhaobo Jiao Yinhou Ma Wensheng
    2013, 11(2):126-132. DOI: 10.6052/1672-6553-2013-018
    [Abstract](2116) [HTML](0) [PDF 630.38 K](2245)
    The flow field of 3-D rotor-seal system was developed, and the characteristics of compressible gas flied for the system were researched by Computational Fluid Dynamics (CFD) technology. The empirical parameters and experimental parameters of the Muszynska gas exciting force model were further identified by the computational results, which made it more suitable for the rotor-seal system. The nonlinear dynamic analysis of the rotor-seal system applied the power series model of the rotor-seal system obtained by power series expansion. The multiple scale method was used to obtain the bifurcation equations of the rotor-seal system in the 1:2 subharmonic resonance case. Based on the singularity theory and Hopf theory, the 1:2 subharmonic resonance transition sets and the existing condition of the supercritical Hopf bifurcation and subcritical Hopf bifurcation were obtained. The subcritical Hopf bifurcation of the rotor-seal system was inhibited by parameter control to improve the system stability.
    10  An overview onmulti-agents cooperative control of unmanned ground system
    Wang Ronghao Xing Jianchun Wang Ping Wang Chunming
    2016, 14(2):97-108. DOI: 10.6052/1672-6553-2015-009
    [Abstract](2087) [HTML](0) [PDF 1.87 M](4563)
    Based on the current research status of multiagents system control theory and technology, the paper makes a detailed overview for unmanned ground systems. From two aspects of behaviour and task cooperative control for multiagents, the relevant theory and application problem is discussed. Moreover, some existed open problems are presented and a possible future development is proposed. For unmanned ground systems, cooperative control will be of great importance in promoting social and military benefits and maximizing the executive function of ground mission.
    11  The measuring method of kinematic vector paramete
    2014, 12(3):248-252. DOI: 10.6052/1672-6553-2014-055
    [Abstract](2055) [HTML](0) [PDF 321.14 K](1849)
    The measuring method used to measure kinematic vector parameters was researched. The generalized kinematics model of vector measuring device and a mathematical model with compensation were established, consequently, the simplified model of the separated sensor movement was obtained. Afterwards, based on the sensor movement described by the balance of electromagnetic and electrostatic support and compensation, the kinematics equations of generalized electromagnetic force system for the sensor were derived. Analysis results show that the use of the compensation model can establish a new modular vector measuring device, thus, the influence owing to the analysis of lateral connections is solved.
    12  Flutter analysis of 2-d aircraft wings in supersonic flow
    Ye xin Chen Yushu
    2014, 12(3):201-204. DOI: 10.6052/1672-6553-2014-048
    [Abstract](2039) [HTML](0) [PDF 296.79 K](3480)
    Non-linear factors cannot be avoided in the design of aircraft structures. In this paper, a two-degree-of-freedom airfoil and cubic stiffness nonlinearities in pitching degree-of-freedom operating in supersonic flight speed regimes has been analyzed. The averaging method and the theory of flutter were used to analyze the nonlinear dynamic system of the dualistic airfoil in the supersonic flow. Then the correctness of the theoretical calculation was verified by numerical calculation, and the analysis result was given.
    13  Dynamcis and control of an oscillator with viscoelastic item
    Luo Jiawei Xu Xu
    2014, 12(3):210-214. DOI: 10.6052/1672-6553-2013-104
    [Abstract](2039) [HTML](0) [PDF 996.46 K](2513)
    The paper presents a detailed analysis on the dynamics and delayed state feedback control of an oscillator with generalized visco elastic item. The trivial equilibrium of the model is first investigated and shows that uncontrolled model exhibits complicated unbounded behavior. Then a velocity feedback control is introduced to stabilize this unstable system. It shows that the velocity feesback control can stabilize the system. And with properly chosen delay and gain in the delayed feedback path, the velocity controlled model may have stable equilibrium, or periodic solutions resulted from the Hopf bifurcation, codimension 2 bifurcation or complex stranger attractor. Some numerical experiments verify the theoretical analysis.
    14  On-orbit load computation and analysis of flexible solar array for china space station
    Liu Fang Guo Qiwei Wu Song Xiao Yuzhi
    2014, 12(3):230-234. DOI: 10.6052/1672-6553-2014-052
    [Abstract](1972) [HTML](0) [PDF 1.16 M](2429)
    In order to ensure the huge energy for normal working of China Space Station and less weight costs in launching, China Space Station adopted the large area flexible solar array (LAFSA) design scheme. The LAFSA has complex structures and extremely low frequency, and bearing loads produced by multiple large maneuver procedure in orbit running, so the strength check and parameter design for each load carrying component become very important segments for the mission's success or failure of China Space Station. This paper established a simplified linear modal for the flexible solar array of China Space Station from the perspective of engineering applications, and computed the loads of every important component of the flexible solar array in on orbit large maneuver procedures, which can be used as the instruction for strength check and lightweight design of the LAFSA.
    15  Advances in nonlinear models for transverse vibration of axially moving beams
    Ding Hu Chen Liqun Zhang Guoce
    2013, 11(1):20-30. DOI: 10.6052/1672-6553-2013-004
    [Abstract](1967) [HTML](0) [PDF 766.90 K](2264)
    This paper summarized the advances in two transverse models for nonlinear vibration of axially moving beams. Based on a nonlinear model for planar vibration of axially moving beams with coupled transverse and longitudinal motion, the derivation of two nonlinear models of transverse vibration was reviewed. The comparisons between approximate analytical results based on the two models for free, forced and parametric vibration of axially moving beams were surveyed. The deviations of the numerical solutions to the two transverse models from the solution to the coupled equation for different vibrations were also summarized. Some problems for further investigations were discussed.
    16  Review and prospect on the research of aero-engine casing dynamics
    Wen Dengzhe Chen Yushu
    2013, 11(1):12-19. DOI: 10.6052/1672-6553-2013-003
    [Abstract](1962) [HTML](0) [PDF 530.95 K](4079)
    The dynamics of the whole aero-engine system has always been the important part that cannot be neglected in the research and design of the engine, as the framework of the engine, the vibration of the casing directly reflects the level of the whole aeroengine vibration. In this paper, an analysis was made on the research of the problems and fault classification of aero-engine casing dynamics, and an overview was made on the research of present situation, development trend, problems and solutions of the domestic and foreign of casing dynamics, which expanded the present situation of the Inclusiveness problems of aero-engine casing dynamics. Finally, some proposals were put forward for the development of the casing dynamics suitable for our country aero-engine technology level.
    17  Space structure vibration control based on passive nonlinear energy sink
    Yang Kai Zhang Yewei Chen Liqun Ding Hu Zang Jian
    2014, 12(3):205-209. DOI: 10.6052/1672-6553-2014-059
    [Abstract](1961) [HTML](0) [PDF 467.15 K](3826)
    This paper investigated the passive nonlinear vibration control method used for energy absorbing in structures of spacecrafts. The structure and the dynamic model of the nonlinear energy sink which could adapt to the space environment were proposed. As nonlinear spring could not be acquired easily in reality, we proposed a new design for the NES based on employing an asymmetric NES force which was generated by two pairs of aligned permanent magnets. Then, the dynamic model for a cantilever beam structure coupled with nonlinear energy sink had been built theoretically. In addition, the passive vibration suppression effect of the nonlinear energy sink on the cantilever beam structure under transient excitation had been analyzed through Galerkin method and numerical analysis method. The results showed that the NES acquired up to 92% dissipation of the system energy imposed by shock excitation, hence the NES could adapt to the space environment and improve the reliability of space system.
    18  Structure-preserving analysis of 2D deploying process for solar power receiver of solar power satellite
    Wang Xindong Hu Weipeng Deng Zichen
    2015, 13(6):405-408. DOI: 10.6052/1672-6553-2014-032
    [Abstract](1929) [HTML](0) [PDF 556.55 K](1738)
    The constraints default phenomenon is a serious problem in solving the Itype Lagrange equation with traditional numerical method. For the simplified 2D model of the solar power receiver of Solar Power Satellite (SPS), the symplectic method is used to analyze the deploying process of the solar power receiver and the constraints default is discussed in this paper. Firstly, based on the Hamilton variational principle, the canonical equation is derived from the EulerLagrange equation that describe the deploying process of the solar power receiver. And then, the symplectic PRK scheme for the canonical equation is constructed. Finally, the deploying process of the solar power receiver is simulated by the symplectic PRK scheme. From the simulation results, it can be concluded that the symplectic PRK scheme constructed in this paper can satisfy the displacement constraint of the 2D system well for a long time.
    19  Bifurcation and chaos of beam subjected to moving loads and random excitations
    Li Haitao Qin Weiyang Tian Ruilan
    2015, 13(6):417-422. DOI: 10.6052/1672-6553-2015-010
    [Abstract](1859) [HTML](0) [PDF 2.10 M](1958)
    moving loads pass through the rough surface of beam. Considering the characteristics of random excitation, present nonlinear model of moving loads different beam roughness. The critical condition in of mean square is obtained by random Melnikov process. The response of structure under the combin of random and periodic excitation is simulated, and used to the variation of dynamic behaviors. It is concluded that speed, nonlinear dynamic behaviors midspan of beam are severely influenced by the random excitation. Therefore poor flatness of surface would increase the probability of occurrence of chaos.
    20  Flapwise characteristics of a wind turbine blade with large deflection
    Liu Qikuan Li Liang Zhang Zhijun Li yinghui
    2012, 10(2):171-176.
    [Abstract](1813) [HTML](0) [PDF 451.51 K](1467)
    The characteristics of flap vibration of a wind turbine blade with large deflection were studied. The governing equation of the vibration under unsteady aerodynamic loads, whose expressions were derived from the Greenberg expressions, was established by applying the Hamiltonian principle. The RayleighRitz method was used to calculate frequencies and mode functions. Based on these mode functions, the partial differential equation governing the vibration was discreted by using the Galerkin’s method. The displacement was resolved to static displacement and dynamic displacement, and the equations of the static and dynamic displacement were obtained. The effects of the inflow ration to the static displacement and the aerodynamic damping were discussed. The dynamic response was analyzed by using the nonlineardynamical tools. The results show: 1) that the static displacement rises with the inflow ratio, and it reaches the limit at the blade tip; 2) that the vibration is a harmonic motion for small inflow ratio, and it becomes a quasiharmonic motion when the inflow ratio is big.

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