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    2020,18(3):1-4, DOI: 10.6052/1672-6553-2020-069
    Abstract:
    As one of part of dynamics and control research field, the development of vehicle system dynamics and control has attracted more and more attentions in recent twenty years. Getting benefits from railway traffic quickly development and huge found from government of China, railway vehicle filed has achieved many important progresses continuously in fundamental research, technology research, product development and so on. Starting from development trend, characteristics and the main problems in operating of railway vehicle in China, this paper focus on the research achievements in load analysis, vibration and noise reducing, modeling and simulation, new structure designing, health state identification of the key rotating parts and so on. These research content represents the key problems and study methods of authors in some degree, and may be useful to other researchers in railway vehicle system dynamics and control filed.
    2020,18(3):5-15, DOI: 10.6052/1672-6553-2020-021
    Abstract:
    随着列车速度的不断提高,轮轨与线路之间的作用力加剧,轮轴的工作状况愈加恶劣,而轮轨载荷与高速轨道交通系统的安全性和可靠性紧密相关.本文以国内某型动车组轮轨载荷为研究对象,制作了测力轮对,在大西线上完成了线路测试.对获得的轮轨力时间历程进行数据处理,并按不同速度等级、线路区段、每一趟往返等不同工况进行抽样和统计,编制64级时域载荷值谱和峰谷值谱,分析其变化趋势及原因.结果表明,轮轨垂向载荷一般为正态分布,波动中心为静轮重;横向力一般围绕零值波动.列车运行速度对轮轨垂向力和横向力波动范围影响明显,且速度越高,波动范围越大.列车上下行工况对轮轨力几乎无影响.曲线半径越小,轮轨力变化越大.车辆空载和满载状态对轮轨垂向力有影响,对横向力影响不明显.本文得出的载荷特征及影响因素为后续轮轨疲劳及动力学研究提供试验和理论基础.
    2020,18(3):16-21, DOI: 10.6052/1672-6553-2020-030
    Abstract:
    In order to achieve a fast and efficient transportation capacity of China"s railways for large, heavy and valuable goods, CRRC TangShan Co., Ltd. developed a high-speed freight Electric Multiple Units (EMU) equipped with four double-axle bogies. Based on the theory of multi-body system dynamics, this paper established a vehicle dynamics model of the high-speed freight EMU equipped with four double-axle bogies, and studied the influence of primary positioning stiffness on the nonlinear critical speed of the vehicle; At the same time, the influence of primary positioning stiffness on vehicle safety index and stationarity index were studied. The results showed that the nonlinear critical velocity firstly increases and then decreases with the increase of the primary longitudinal positioning stiffness, and monotonically decreases with the increase of the primary lateral positioning stiffness. The lateral stability index of the vehicle increases with the increase of the primary longitudinal positioning stiffness, while the vertical stability index is nearly unchanged. The primary lateral positioning stiffness of the vehicle has no significant effect on the vehicle stability index.
    2020,18(3):22-30, DOI: 10.6052/1672-6553-2020-026
    Abstract:
    A three-module marshaling model for a 100% low floor light rail vehicle with longitudinal coupled side-motor drive bogies was built by using the multi-body dynamics simulation software SIMPACK. The main plenum, orifice, and additional plenum of the central suspension air spring were modeled by MATLAB/Simulink. The operating conditions of the 100% low-floor light rail vehicles were set, and the feasibility of using air springs in the 100% low-floor light rail vehicle were analyzed by co-simulation combining SIMPACK and MATLAB/Simulink. The results indicated that both the vehicle stability and curve passing ability are improved after using the air spring. Specifically, the critical speed of hunting instability is increased to 149km/h, which is higher than the design speed. Both the stability and the maximum acceleration index are less than 2.5 as the vehicle runs. When the vehicle passes through a small-radius curve, all the wheel load reduction ratio, derailment coefficient, wheel lateral force, and wheel rail lateral force are less than the evaluation standard limit, and all the performance indices meet the technical standards of this type of air spring. Therefore, the application of air spring to the 100% low-floor light rail vehicle is feasible.
    2020,18(3):31-37, DOI: 10.6052/1672-6553-2020-022
    Abstract:
    An active control method for the stability of a high-speed train was proposed based on the lateral vibration of the bogie frame. Two implementation schemes, namely the lateral vibration control of the frame by the inertial actuator and the active elastic suspension of the power bogie drive system, were carried out. The vehicle hunting stability index and control force were utilized as two objective functions, and the genetic algorithm (NSGA-II) was used to optimize the control parameters and suspension parameters of the drive system. The results showed that the lateral vibration control of the frame can effectively improve the stability of the bogie, and the time delay of the control system can easily cause system instability, when the direct state feedback of the frame is realized to control the frame vibration. Subsequently, state feedback of additional oscillator was proposed to reduce the influence of time delay. The results showed that reasonable parameters of the additional oscillator can improve the vehicle system stability. A stiffer additional oscillator can increase the critical speed margin of the vehicle system, but it can cause system instability for a certain time delay. Therefore, it is necessary to take into account both the hunting stability of the bogie and the stability of the control system for optimizing the parameters of the additional oscillator. Finally, for the 350 km/h high-speed train bogie, the optimum natural frequency and damping ratio of the additional oscillator were obtained.
    2020,18(3):38-43, DOI: 10.6052/1672-6553-2020-025
    Abstract:
    In order to improve the ride comfort of trains at high speed, the semi-active hybrid control of a train suspension was studied. A two-degree-of-freedom vehicle model was established to analyze and compare the on-off control strategy and continuous control strategy. Based on the analyses of transmission characteristics, a hybrid control strategy was proposed, and the influence of adjustment coefficient on the hybrid control strategy was studied. In order to verify the effectiveness of the control strategy, a full-vehicle model was established based on UM and Simulink. The control strategy was applied to the secondary lateral shock absorber, and the simulation analysis was carried out. The results showed that the hybrid control strategy can take into account the advantages of both on-off and continuous control strategies, the lateral acceleration of the car body is reduced and the lateral stability of the train is improved, when the adjustment coefficient is selected properly.
    2020,18(3):44-50, DOI: 10.6052/1672-6553-2020-023
    Abstract:
    The modal superposition method was used to obtain the admittance characteristics of damped wheels. Based on the established prediction model of wheel/rail rolling noise and taking the surface roughness of wheels and rails as the excitation, the influence of the position and thickness of a damping layer on vibration and sound radiation characteristics of damped wheels was analyzed. Firstly, a three-dimensional solid finite element model of damped wheels was established, and the Block Lanczos method was used to calculate the modal characteristics of wheels. Secondly, the frequency response function of wheels under unit load was obtained by the modal superposition method. Then, the frequency domain vibration characteristics of wheels under the excitation of roughness spectrum were obtained by the virtual excitation method. Finally, the frequency domain characteristics of acoustic radiation were obtained by an analytic method based on the dynamic responses. The results showed that the damping layer laid on the wheel web has no obvious effect on vibration and noise suppressions of the wheel below 1000Hz, but performs good function above 1600Hz. The noise reduction by the damping layer laid on both sides of the web of the wheel is better than that by the damping layer only laid on one side. The thicker the thickness of the damping layer is, the more obvious the noise reduction is.
    2020,18(3):51-55, DOI: 10.6052/1672-6553-2020-028
    Abstract:
    A generalized multi-step explicit integration method (GMEM) was used to improve the computational efficiency for nonlinear rail vehicle dynamics. The increment formulation of the explicit integration algorithm was developed for nonlinear systems. The train dynamic model consisting of the vehicle and couplers, etc., was established. Both the coupling impacts and the medium- and low-speed collisions of the vehicles were studied by using the GMEM. The results indicated that the GMEM is endowed with good stability in the testing examples. The computational speed of the GMEM is approximately 3.8 times of that of the Runge-Kutta method. The locking phenomenon occurs in the transition stage for the dry friction coupler model. The carbody acceleration oscillates with high frequencies due to the locked state in the train impact. Therefore, the GMEM is appropriate for the simulation of the nonlinear rail vehicle dynamics.
    2020,18(3):56-61, DOI: 10.6052/1672-6553-2020-032
    Abstract:
    铁道车辆临界速度与很多参量有关,如何准确有效地建立它们之间的函数关系进行不确定性研究是一个比较复杂的问题.基于此,推导高维多阶基于正态分布场的Hermite正交多项式,采用拉丁超立方采样的配点方式建立某转向架临界速度与随机参量之间的函数关系.分析了不同变异系数下转向架悬挂系统部件左/右、前/后均服从独立正态分布时临界速度的变化规律.可靠性分析的结果表明:随着变异系数的不断增大,只有取较低的临界速度限定值,才能保证转向架系统具有低的失效概率.灵敏度分析的结果则显示:二系悬挂横向阻尼对临界速度影响最大,不同的前/后悬挂部件对临界速度有着不同的重要性影响,变异系数的变化不会根本性改变参量的灵敏度指标排序.
    2020,18(3):62-70, DOI: 10.6052/1672-6553-2020-029
    Abstract:
    The steering performances of wheels with different coupling modes are obviously different. The dynamics models of a bogie with traditional wheelset, independent rotating wheel, longitudinal coupling wheel and elastic damping coupling wheelset were established, respectively, and the guiding mechanism and the generation of longitudinal creep forces were analyzed. The results showed that the traditional wheelset can produce longitudinal creep forces with the same size and opposite direction and has the best guiding ability. Independent rotating wheels cannot generate longitudinal creep forces, and the guidance can be fulfilled only by the wheel edge when the train passes through curved lines. The longitudinal coupling wheel also can generate longitudinal creep forces with the same size and opposite direction, and its guiding ability is better than the independent rotating wheel. The generating mechanism of the longitudinal creep forces produced by the elastic damping coupling wheelset is almost consistent with that of the traditional wheelset, and its guiding performance is slightly worse than the traditional wheelset, but better than the longitudinal coupling wheel.
    2020,18(3):71-78, DOI: 10.6052/1672-6553-2020-031
    Abstract:
    利用仿真软件UM建立了重载货车动力学模型,研究了闸瓦制动力不均衡状态下轮轨动态特性.以紧急制动工况为例,分别对一、二位轮对施加左、右轮不一致的闸瓦压力,得到了车辆直线运行时的轮对运行姿态和轮轨动态接触行为.研究结果表明,随着闸瓦压力的不均衡程度增加,轮对横移量会显著增大,并且不均衡闸瓦压力对一位轮对轮轨动态行为的影响要大于二位轮对,产生上述区别的主要原因是:蠕滑力引起的转向架总体摇头方向和受力轮对的摇头方向是否一致.进而考虑轮、瓦摩擦制动力矩的影响,发现在闸瓦压力较小时,制动力矩对轮对横移量和摇头角会产生一定影响,但就整体趋势而言,不均衡闸瓦压力的影响更为显著.
    2020,18(3):79-85, DOI: 10.6052/1672-6553-2020-020
    Abstract:
    Considering the gap between the wheel and axle, the dynamic model of a three-piece and gauge-changeable truck was established, and the running performance of the vehicle and the wheel-rail contact characteristic of LM tread on both the standard and broad gauge tracks were investigated. The LM tread with gauge 1435 mm and 1520 mm, the rail inclination 1/40 and 1/20, and the standard and worn rail profiles were selected for parameter analysis. It was found that the compatibility of LM tread for two kinds of rail inclinations is good, but it is sensitive to the change of the bottom slope after tread wear. Moreover, the LM tread is sensitive to the transverse gap the wheel and axle on the standard line, but insensitive on the wide rail line. The transverse and rotational gaps lead to a reduction in the critical speed of the vehicle, which are recommended to be selected within 0.6mm and 0.5mrad, respectively. However, the gaps do not affect the safety and smoothness of the vehicle operation, and the dynamic performances of the vehicle on the standard and wide rail lines are almost the same. During the operation of the gauge-changeable vehicle, both the transverse force and longitudinal creep force between the wheel and rail lead to dynamic changes of the transverse and rotational gaps. Finally, the normal distribution statistics of the axle-gap and wheel-rail loads were conducted, which indicated that the axle-gap load is equal to the wheel-rail load.
    2020,18(3):86-92, DOI: 10.6052/1672-6553-2020-027
    Abstract:
    安全域是一种从域的角度描述轮对轴承可安全运行区域的定性模型.然而,高速列车运行状态的样本数据通常是正常样本,故障样本的缺乏意味着只能使用正常样本进行安全域建模.支持向量数据描述是一种单分类方法,可以只利用一类样本进行建模.现有的滚动轴承安全域建模方法基本采用的是批量学习算法,而在样本数据不断增加的情况下,批量算法的效率低下.因此,本文将增量支持向量数据描述方法引入轮对轴承的故障诊断领域,提出了一种基于样本增量学习的高速列车轮对轴承安全域的建模方法.实验结果表明,相比于传统批量学习算法,本文提出的方法在轮对轴承安全域的建模中更加高效,并且分类准确率基本不受影响.
    2020,18(3):93-99, DOI: 10.6052/1672-6553-2020-024
    Abstract:
    Optimal wavelet filter is one of the most useful methods in fault diagnosis of rolling element bearings. Aiming at finding out an optimal couple of center frequency and bandwidth of the wavelet filter, and considering the impulsiveness and cyclostationarity of faulty signals, a novel method based on negentropy and multi-objective optimized complex Morlet wavelet filter was proposed. The parameters of the wavelet filter were optimized by the improved non-dominated sorting genetic algorithm (NSGA-II), to maximize the negentropy of both the envelope and the envelope spectrum. And then, the resonance band rich in fault information was determined by the average negentropy of the Pareto set for demodulation. The experiment results validated the effectiveness in extracting repetitive transients with complex interferences and in identifying the faults of wheel-set bearings exactly.
    2020,18(3):100-106, DOI: 10.6052/1672-6553-2020-033
    Abstract:
    A novel adaptive empirical wavelet tower decomposition method was proposed to solve the problem that the weak fault features of gears are difficult to be diagnosed under strong background noise. Firstly, the Fourier transform was utilized to process the vibration signals of gear faults. The frequency spectrum of a signal could be effectively segmented according to the number of decomposition layers, and the empirical wavelet transform (EWT) was applied to extract the intrinsic modes of the signal. Secondly, the time-frequency kurtosis index was proposed to evaluate the performance of mode signals. Then the time-frequency kurtosis diagram of all mode signals under different decomposition layers was acquired to determine the frequency band range of the optimal mode signal. Finally, weak fault features of gears were extracted through envelope demodulation analysis for the optimal mode signal. Experimental results showed that the proposed method can effectively improve the weak fault detection of gears, and eliminate the errors caused by the strong background noise, which outperforms the traditional EWT method.
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    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(1):18-23, DOI: 10.6052/1672-6553-2013-068
    [Abstract] (1857) [HTML] (0) [PDF 1.13 M] (2564)
    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.
    2014,12(3):193-200, DOI: 10.6052/1672-6553-2014-046
    [Abstract] (1847) [HTML] (0) [PDF 748.46 K] (2386)
    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.
    2017,15(5):385-405, DOI: 10.6052/1672-6553-2017-039
    [Abstract] (930) [HTML] (0) [PDF 1.91 M] (2329)
    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):243-247, DOI: 10.6052/1672-6553-2014-054
    [Abstract] (1608) [HTML] (0) [PDF 1.07 M] (2260)
    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.
    2014,12(3):225-229, DOI: 10.6052/1672-6553-2014-051
    [Abstract] (1378) [HTML] (0) [PDF 1.38 M] (2251)
    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] (2234) [HTML] (0) [PDF 336.30 K] (2209)
    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.
    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(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.
    2014,12(3):253-258, DOI: 10.6052/1672-6553-2014-056
    [Abstract] (1333) [HTML] (0) [PDF 1.00 M] (1711)
    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.
    2016,14(3):247-252, DOI: 10.6052/1672-6553-2015-052
    [Abstract] (1039) [HTML] (0) [PDF 2.18 M] (1676)
    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] (1069) [HTML] (0) [PDF 2.22 M] (1674)
    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.
    2016,14(2):97-108, DOI: 10.6052/1672-6553-2015-009
    [Abstract] (1132) [HTML] (0) [PDF 1.87 M] (1670)
    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] (1286) [HTML] (0) [PDF 530.95 K] (1640)
    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.
    2014,12(3):205-209, DOI: 10.6052/1672-6553-2014-059
    [Abstract] (1419) [HTML] (0) [PDF 467.15 K] (1601)
    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):283-288, DOI: 10.6052/1672-6553-2014-061
    [Abstract] (1763) [HTML] (0) [PDF 479.50 K] (1596)
    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(3):201-204, DOI: 10.6052/1672-6553-2014-048
    [Abstract] (1528) [HTML] (0) [PDF 296.79 K] (1583)
    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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