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    2022,20(2):1-14, DOI: 10.6052/1672-6553-2021-054
    Abstract:
    Multi-target space exploration is one of the options for economic, rational and sustainable space exploration ,and it can achieve huge benefits at a low cost. Due to the huge and complicated optimization space and difficulties of optimization, multi-target space trajectory optimization is a topic that attracts lots of research. Intel-ligent methods are suitable for solving these problems. In this paper, multi-target space trajectory optimization is discussed by introducing trajectory optimization competitions in which intelligent methods are playing more and more important roles. Then this paper reviews transfer trajectory intelligent optimization methods and sequence intelligent optimization, and the conclusion is drawn at last.
    2022,20(2):15-21, DOI: 10.6052/1672-6553-2021-051
    Abstract:
    Herglotz conservation laws of nonholonomic mechanical systems in event space are studied. The Herglotz generalized variational principle in event space is given, and the Herglotz -d' Alembert principle, a new differential variational principle for nonholonomic mechanical systems in event space, is derived by introducing non-holonomic constraints and using the Holder definition of commutative relation. The transformation of the invariance condition of Herglotz-d' Alembert principle is established by introducing space generators and parameter generators in the event space. Herglotz conservation theorem and its inverse for nonholonomic nonconservative mechanical systems in event space are constructed based on this principle. As particular cases, the Herglotz conservation laws in configuration space and the Herglotz conservation laws for holonomic mechanical system in event space are given. An example is given at the end of the paper to illustrate the application of Herglotz conservation laws.
    2022,20(2):22-35, DOI: 10.6052/1672-6553-2021-055
    Abstract:
    Neurons within pre-Botzinger complex have been found experimentally to exhibit different firing activities. One special firing pattern observed in experiment is the so called mixed bursting ( MB ) characterized by combining two or more different types of short bursts within each cycle of a periodic bursting solution. Using phase-plane analysis, fast-slow decomposition, ISI bifurcation, one-parameter and two-parameter bifurcation analysis, we investigate effects of the calcium-activated nonspecific cationic conductance (gcAN) and the maximal SERCA( Fserca ) on the firing activities of the pre-Botzinger complex, especially the mixed bursting pattern. We determine parameter region of Fserca when concentration of calcium changes periodically and propose the generation and transition mechanism of the bursting activities. The results demonstrate that the calcium-activated nonspecific cationic current and Fserca will affect types of neuron bursting and cause mixed bursting.
    2022,20(2):36-44, DOI: 10.6052/1672-6553-2021-052
    Abstract:
    Combining with bifurcation theory in dynamical systems, a nonlinear ( 3 + 1 ) -dimensional modified KdV-Zakharov-Kuznetsov equation is theoretically investigated. Firstly, based on different parameter values and discriminant in cubic equation, types of equilibria and their corresponding phase portraits are qualitatively analyzed ,respectively. Secondly, by the Jacobi elliptical functions, formulas of some bounded traveling wave solutions and homoclinic loops are formally obtained, extending results in literature. Finally, several multi-mode approximations are numerically presented via Hamiltonian method, which indicate periodicity of bounded traveling wave solutions.
    2022,20(2):45-49, DOI: 10.6052/1672-6553-2021-048
    Abstract:
    The delayed synchronization of chaotic Lur'e system is studied. By constructing an appropriate augmented Lyapunov-Krasovskii functional, the augmented vector contains not only a single integral term and a double integral term, but also an augmented triple integral term. When estimating the derivative of the Lyapunov-Kra-sovskii functional, a free matrix is introduced through the zero equality. By using the integral inequality, the sufficient condition for the delayed synchronization of chaotic Lur'e systems is given in the form of linear matrix inequalities. Finally, numerical example demonstrates effectiveness of the proposed method.
    2022,20(2):50-61, DOI: 10.6052/1672-6553-2021-059
    Abstract:
    This paper is aimed at investigating galloping behavior of iced catenary. The nonlinear motion equations of the iced catenary are established where the cross-section shape of the iced contact wire differs from the one of the iced messenger wire. The galloping characteristics of the iced catenary and the effects of the icing thickness are studied. The results indicate that dominant frequency, intensity of beat vibration, track and maximum vertical/lateral displacements of each span of the iced catenary may be different but are symmetric with respect to the center of the catenary. The geometric nonlinearity of the iced catenary makes the system more stable. Compared with the contact wire, variation of the icing thickness of the messenger wire makes nonlinear critical wind speed of the iced catenary vary more greatly. The larger the icing thickness, the smaller the linear critical wind speed, but there is a basic unstable area that is almost independent of the icing thickness.
    2022,20(2):62-70, DOI: 10.6052/1672-6553-2021-049
    Abstract:
    The dynamic stability of thin shell with variable speed rotation is studied in this paper. Based on Donnell thin shell theory, vibration differential equation of cylindrical shell is established, which considers both variable speed and periodic axial force. The analytical expressions for boundaries of both primary and combined instability regions are derived by multiscale method. Variations of instability boundaries with excitation frequency and amplitude are discussed in three cases, i. e. , only periodic axial force, only variable speed rotation and both two time-varying factors. The analytical results are verified by comparing with literature results and numerical results.
    2022,20(2):71-77, DOI: 10.6052/1672-6553-2021-053
    Abstract:
    In this paper, aiming at the lateral low-frequency swaying of a high-speed locomotive body, a suppression method is proposed to replace the traditional anti-hunting damper by a frequency-selective-damper (FSD) . Firstly, the dynamic model of the locomotive is established by Simpack, and the characteristics of lateral low-frequency swaying of the car body are analyzed think distribution of the car body vibration. The analysis shows that the lateral swaying frequency of the car body ranges from 1 to2, being distinguished from other lateral vibrations. Then, the CFD model of frequency valve and the numerically simplified model of FSD are established. Finally, the results of lateral vibration of vehicles with traditional yaw damper and FSD are compared in frequency domain. The results demonstrate that a FSD damper instead of traditional yaw damper can significantly improve carbody hunting stability and reduce the amplitude of low frequency swaying of the locomotive due to the lower damping coefficient in low-frequency condition. At the running speed of 160km/h, the peak values around the main frequency of lateral acceleration and yaw acceleration decrease by 42% and 37.5% , respectively effectively reducing the low-frequency sway of the locomotive.
    2022,20(2):78-87, DOI: 10.6052/1672-6553-2021-062
    Abstract:
    The dynamic behavior of thin plate under impulsive loading is of high complexity, characterized by large deformation, instantaneity, and severe nonlinearity. When a thin plate is subjected to a shock wave of low impulse, abnormal dynamic response is prone to occur. However, effects of loading characteristics on the abnormal dynamic response of thin plate are not clear. An impulsive loading model validated by experimental data is successfully used to simulate the counter-intuitive response of a thin square plate, and then the effects of negative pressure and decaying parameter on the abnormal dynamic response are studied. Finally, when the stand-off distance increases with a fixed scaled distance, four different modes-secondary intuitive, counter-intuitive, mixed, and initial intuitive modes-are found. The relationship between the different dynamic behavior modes and the plastic dissipation energy is examined.
    2022,20(2):88-96, DOI: 10.6052/1672-6553-2021-058
    Abstract:
    In order to study collision response of trains with different train lengths, a one-dimension longitudinal collision simulation platform is established based on the Zhai method. The one-dimensional longitudinal collision simulation platform is validated by comparing impact responses of the same train grouping, such as speed and energy, with results of the one-dimension longitudinal collision simulation platform. On the basis of this platform, the collision responses of active and passive trains under the same and different train setting conditions are studied by taking the speed, acceleration and absorbed energy of the vehicle as the indexes. The results demonstrate that when the train setting length of the active vehicle is the same, the velocity at the end of the collision will decrease with increased train setting length, and the energy absorption ratio will increase with increased train setting length. When the length of the active vehicle is longer than that of the passive vehicle, the energy absorbed by the collision is less and the remaining kinetic energy is larger, thus meaning that the collision will be more dangerous.
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    2014,12(3):193-200, DOI: 10.6052/1672-6553-2014-046
    [Abstract] (2077) [HTML] (0) [PDF 748.46 K] (4411)
    Abstract:
    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.
    2014,12(1):18-23, DOI: 10.6052/1672-6553-2013-068
    [Abstract] (2144) [HTML] (0) [PDF 1.13 M] (4279)
    Abstract:
    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.
    2015,13(5):361-366, DOI: 10.6052/1672-6553-2014-064
    Abstract:
    Dynamic and control systems often contain uncertain parameters that may result in uncertain predictions. In the interest of quantifying the effects of parameter uncertainties on response variability, this paper develops a stochastic response surface based method for the sensitivity analysis of uncertain parameters. Stochastic response surfaces were firstly constructed to describe the explicit relationships between uncertain parameters and responses. Then partial derivations were performed on the mathematical expressions of stochastic response surfaces in order to obtain sensitivity indices that simultaneously embody the effects of parameter means and standard deviations. Lastly, the developed method has been verified against a numerical cantilever beam containing uncertain geometric and material parameters. The sensitivity analysis results were compared with those given by the analysis of variance method.
    2014,12(3):243-247, DOI: 10.6052/1672-6553-2014-054
    [Abstract] (1926) [HTML] (0) [PDF 1.07 M] (4060)
    Abstract:
    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.
    2017,15(5):385-405, DOI: 10.6052/1672-6553-2017-039
    [Abstract] (1226) [HTML] (0) [PDF 1.91 M] (4006)
    Abstract:
    In this review article, the growth and related academic communications in the dynamics of multibody systems are firstly surveyed. Then, the recent advances in the numerical algorithms for solving the dynamic equations of flexible multibody systems, the contact/impact dynamics of flexible multibody systems and the deployment of flexible space structures are systematically reviewed, together with several open problems of concern. Finally, some suggestions are made for the prospective researches on the dynamics of flexible multibody systems.
    2014,12(3):225-229, DOI: 10.6052/1672-6553-2014-051
    [Abstract] (1589) [HTML] (0) [PDF 1.38 M] (3689)
    Abstract:
    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.
    2014,12(3):269-273, DOI: 10.6052/1672-6553-2014-043
    [Abstract] (2442) [HTML] (0) [PDF 336.30 K] (3661)
    Abstract:
    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.
    2012,10(1):21-26, DOI:
    Abstract:
    A discrete finite dimensional dynamical model was built to describe the space large overall motion of tethered satellite system with an infinite dimensional viscoelastic tether in a long time. The tethered satellite system is a complex nolinear dynamic system. Considering the tether’s viscoelasticity, distributed mass and space form, the established improved bead model can meticulously describe the tether’s vertical and horizontal vibration. According to tether’s characteristic of tensile and not compressive, the slack tether unit model was set up to accurately reflect real stress of tether. The determination of the number of degrees of freedom of the system was studied. Based on numerical integral calculation, the dynamic response was obtained via numerical simulation of the deployment, retrievement and retainment process of tethered satellite system in a long time. The result is convergent. The simulation proves the important role of the stable equilibrium position in the dynamics of tethered space system.
    2008,6(4):301-306, DOI:
    Abstract:
    The problem of P and PI feedback control to a time delay system was investigated,with the emphasis on the determination of the feedback gains that ensured the asymptotical stability of the delayed system. By means of Lambert W function,the feedback gain of P control can be expressed explicitly,so that the optimal feedback gain can be easily obtained. For the system under a PI control,the stable region of the feedback gains was determined on the basis of stability switches and D subdivision,and the optimal feedback gains that enabled the system to admit maximal stable margin were figured out numerically by using Lambert W function. From the viewpoint of computation,the present method is much simpler than the available methods.
    2016,14(2):97-108, DOI: 10.6052/1672-6553-2015-009
    [Abstract] (1397) [HTML] (0) [PDF 1.87 M] (3477)
    Abstract:
    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.
    2013,11(1):12-19, DOI: 10.6052/1672-6553-2013-003
    [Abstract] (1494) [HTML] (0) [PDF 530.95 K] (3254)
    Abstract:
    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.
    2013,11(4):357-362, DOI: 10.6052/1672-6553-2013-041
    Abstract:
    At present, the main task of designing a mounting system of automotive engine powertrain is to select appropriate stiffness, position and angle of mounting components so that free-vibration modal frequency of the mounting system can avert from the exciting-force frequency at the idle speed of the engine and the natural frequency of vibration of the vehicle body and that the decoupling degree of each mode shape is increased as far as possible, so as to improve the vibration-isolation effect of the mounting system. The design of a mounting system based on strict decoupling at predetermined frequencies is to make the modal frequencies of the designed mounting system completely equal to the frequencies predetermined in accordance with the frequency planning of automotive design, and to enable strict decoupling of each mode shape of each mode, i.e., the decoupling degree of vibration energy in every direction equals to 1. Based on a free-vibration equation for a mounting system, this paper presents an equation system for designing a mounting system with strict decoupling at predetermined frequencies, provides a solving method for this equation system by using the theory of generalized inverse matrix or method of constructing function, so as to provide an optimal design method more efficient and simpler than the current modal optimization method of mounting system. Relevant example has validated the correctness of equations and solving method of the strict-decoupling design at predetermined frequencies.
    2014,12(3):253-258, DOI: 10.6052/1672-6553-2014-056
    [Abstract] (1481) [HTML] (0) [PDF 1.00 M] (2996)
    Abstract:
    Taking account of the structural stiffness and the low order vibration frequencies, two schemes of multi-objective topology optimization were proposed to obtain the best aircraft lifting-surface structural design. Based on penalized density theory, the scheme one (named as constrain method) is to convert the multi-objective optimization to single-objective optimization by considering the minimum structural mass as the objective with constraints of reference points displacements and the low order vibration frequencies. The scheme two (named as the combination of constrain method and criterion function method) settles the multi-objective optimization by defining combined compliance index (CCI) as the objective, with the constraints of volume fraction and the low order vibration frequencies. The CCI is the function of structural compliance and low order vibration frequencies. Numerical results demonstrate the proposed schemes not only realize reducing the structural mass but also raise the first and second order frequencies.
    2014,12(3):283-288, DOI: 10.6052/1672-6553-2014-061
    [Abstract] (2019) [HTML] (0) [PDF 479.50 K] (2984)
    Abstract:
    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.
    2014,12(2):183-187, DOI: 10.6052/1672-6553-2014-025
    Abstract:
    PMSM due to little harmonic, high precision torque, commonly is used in the servo system and the high performance speed control system. In this paper,the physical model of PMSM is simplified and the mathematical model of the motor is established in order to facilitate research.Thispaper uses id=0 control manner which is the simplest manner is vector control methods,motor electromagnetic torque equation is established based on rotor field oriented vector control.The system model, speed and current control block are build and simulated with MATLAB/Simulink.Simulation results shows that the waveform is consistent with thoretical analysis,the model has fast response and small overshoot.The system runs stably with good dynamic and static characteristics. The simulation makes full use of modularization design. All the parameters and their influence on the system can be changed and observed.It also can easily validate the control strategies and select the most suitable one. So this kind of simulation is good for system design and adjusting and validating.
    2016,14(3):247-252, DOI: 10.6052/1672-6553-2015-052
    [Abstract] (1289) [HTML] (0) [PDF 2.18 M] (2971)
    Abstract:
    Tires are the only carrier of the contact between the vehicle and road surface. Their mechanical property is important for analysis and control on the vehicle dynamic response. At present, the tire simulation mostly focuses on the steady state model. But it can not describe the dynamic characteristic of the tire accurately. Therefore, it plays a significant role to add the dynamic tire model in the vehicle dynamics simulation. The tire friction model in the multi body dynamical software ADAMS is static, where the friction is regarded as a static value. However, in actual, the friction between the tire and road surface is dynamic, and it should be a dynamic function of the relative velocity and displacement. To this end, in this paper, the dynamic tire LuGre model using the Matlab/Simulink software is constructed. Through connecting the interface with Adams/Car, co simulation between the vehicle model and the simulink tire model is carried out in order to achieve the dynamic contact between tire and road and improve the accuracy of vehicle system analysis.
    2014,12(1):36-43, DOI: 10.6052/1672-6553-2013-110
    [Abstract] (1288) [HTML] (0) [PDF 2.22 M] (2895)
    Abstract:
    The coupling nonlinear dynamic model of dual rotor system was established by using finite element method, and then the critical speed of revolution and mode shape were calculated by using the software MATLAB. In addition, the unbalance responses of dual rotor system were studied, and the vibration performances in different speeds of dual rotor casing systems were obtained. The research provides a theoretical basis for the design of the dual rotors system in engineering.
    2014,12(3):205-209, DOI: 10.6052/1672-6553-2014-059
    [Abstract] (1662) [HTML] (0) [PDF 467.15 K] (2865)
    Abstract:
    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.
    2014,12(3):201-204, DOI: 10.6052/1672-6553-2014-048
    [Abstract] (1741) [HTML] (0) [PDF 296.79 K] (2792)
    Abstract:
    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.
    2014,12(1):62-66, DOI: 10.6052/1672-6553-2013-097
    Abstract:
    A spline finite point method was presented to study the natural frequency of arch. The displacement mode shape function of the arch free vibration was simulated with a linear combination of cubic B spline. The free vibration frequency equation of arch structures was derived according to Hamilton principle, in which the effect of the dead load was considered. Meanwhile, the effect of the dead load on the natural frequency of arch structures was analyzed. The results show that the natural frequency of arch is reduced. The effect of influence depends on the stiffness of the arch itself. When the arch stiffness is certain, the bigger the rise span ration and the radius to thickness ration, the higher the effect of the dead load on the natural frequency of arch structures.

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