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Research Progress and Challenges for the Optimal Control of Airborne Wind Energy Systems
Pang Yan, Yang YuPeng, Du ZhiWei
2024,22(6):1-10, DOI: 10.6052/1672-6553-2023-114
[Abstract] (78) [HTML] (0) [PDF 912.69 K] (464)
Abstract:
In order to achieve the strategic goal of "carbon peak and carbon neutrality", the development of a high proportion of renewable energy will be promoted continuously in our country. Therefore a new power system based on new energy will formed gradually. As a renewable clean source, the development and utilization of wind energy has become an important research direction. Studies have shown that the wind speed in the higher altitude is stronger and the wind direction is more stable. Therefore, breakthroughs in wind power generation can be achieved by capturing high altitude wind energy. In order to ensure the safe, economical and efficient operation of the high altitude kite power generation system, the design of its control system has extremely high requirements. This paper starts from the basic principles, development history and application status of several high altitude wind power technologies. Then, a typical Yo-Yo structure kite is modeled. Based on this model, the principles and characteristics of various nonlinear control technologies are analyzed, and the principle of nonlinear model predictive control and simulation results of trajectory tracking control are described in detail. It summarizes that the key problems of high altitude wind energy control include that control algorithm calculation is too consuming, the research of control system reliability is lack and the control methods are not intelligent.
Research on Preserving Symplectic Algorithm for Appell Equations of Nonholonomic Systems
Zhang Kexin, Xie Jiafang
2024,22(6):11-15, DOI: 10.6052/1672-6553-2023-127
[Abstract] (61) [HTML] (0) [PDF 341.77 K] (448)
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In this paper, the undetermined tensor method is used to Birkhoffize the Appell equation for a nonholonomic system. The generating functions are obtained according to the construction principle of generating functions, and then a Birkhoff symplectic scheme is given. Finally, a specific example of Appell equation is provided to verify the above theory and simulate this example. The results show that the preserving algorithm is more effective and superior with the evolution of time.
Influence of Micrometeoroid Collisions on the Halo Orbit around the Sun-Earth L₂ Point
Li Qingjun, Wu Yuting, Wang Bo, Huo Zhuoxi, Liu Jilin, Liu Huigen
2024,22(6):16-23, DOI: 10.6052/1672-6553-2023-128
[Abstract] (69) [HTML] (0) [PDF 836.88 K] (456)
Abstract:
There are a large number of high-speed micrometeoroids in space. The collision between micrometeoroids and spacecraft in orbit will lead to orbit deviation, performance degradation, structural damage, or even failure. Due to the instability of the Halo orbit, the effects of micrometeoroid collisions on the dynamic evolution of the Halo orbit around the Sun-Earth L₂ point are studied in this paper. First, an orbital model around the Sun-Earth L₂ is established, and the initial conditions of the Halo orbit are constructed using the differential correction method. Based on the Grün micrometeoroid flux model, the number of collisions between micrometeoroids and spacecraft is calculated. The velocity variation caused by the collision is evaluated. Then, the Runge-Kutta algorithm is used to solve the orbital dynamic equations of the Halo orbit, and the evolution of orbit deviation caused by the collisions is studied. Besides, the state transition matrix method is used to analyze the evolution of the initial state deviation, which is then compared with the numerical integration method. Finally, based on the state transition matrix method, the dynamic responses caused by different magnitudes and directions of the velocity increments are analyzed. It was found that the results obtained by the state transition matrix in a short time are basically consistent with the numerical integration method, while the final deviation can be calculated from the initial deviation with only one matrix multiplication, which is highly efficiency. The results also showed that due to the inherent instability of the Halo orbit, the initial small micrometeoroid collisions would grow rapidly. This may lead to more control fuel consumption and ultimately affect the life of the spacecraft. In addition, the direction of velocity increments caused by micrometeoroid collision has an important effect on the deviation transmission.
Transverse Vibration Analysis of Axially Moving Composite Thin-Walled Beams
Guo Qing, Lv Shiwei, Fu Qiang, Shen Zhenxing
2024,22(6):24-32, DOI: 10.6052/1672-6553-2023-122
[Abstract] (72) [HTML] (0) [PDF 1.57 M] (490)
Abstract:
Dynamics of axially moving laminated composite thin walled beams is studied in the paper. Based on the variational asymptotic method (VAM) for the composite thin-walled beams, and using the Euler Bernoulli beam model and Hamilton's principle, the dynamical equations of the composite thin-walled beam are established. The free vibration of the thin walled beam is analyzed by the assumed mode method, and the accuracy of the modeling approach is verified by comparison to the other approaches. Then, the transverse vibration equation of the axially moving composite thin-walled beams is derived, which is solved numerically by the fourth-order Runge-Kutta method. Lastly, the effects of various fiber lay up techniques and uniform velocities on the tip displacement response are investigated.
Dynamic Modeling of Large Flexible Structures with Force Feedback under Basic Excitation
Li Wei, Du Dong, Zhou Xubin, Feng Yanjun
2024,22(6):33-41, DOI: 10.6052/1672-6553-2023-130
[Abstract] (68) [HTML] (0) [PDF 822.50 K] (457)
Abstract:
Taking the central rigid body and flexible beam as examples, the dynamic modeling of the rigid-flexible coupling system lacking a strong component of mass and inertia is studied in this paper. The simulation results show that the established model can explain the cause of the dynamic stiffening phenomenon and calculate the system frequency at different rotating speeds, which can accurately explain the dynamic stiffening phenomenon of the rigid-flexible coupling system. At the same time, considering the translational motion of the central rigid body, the influence of the mass and inertia of the rigid body on the attitude angular vibration frequency of the system after maneuvering is obtained.
Development and Verification of Overload Simulation Algorithms for Three-Axis Human Centrifuge
Liu Chenhui, Ding Yuxuan, Sun Guangxin, Wang Pengfei, Han Shilei, Wang Cong, Tian Qiang
2024,22(6):42-49, DOI: 10.6052/1672-6553-2024-006
[Abstract] (58) [HTML] (0) [PDF 1.04 M] (446)
Abstract:
High-G training for pilots has commonly performed in the centrifuge-based flight simulators. In this paper, algorithms for overload simulation in a three axis human centrifuge are developed and validated. To this end, a kinematic model is established for kinematic analysis. A moving average algorithm is employed to smooth the inputs and to alleviate the abrupt changes in pitch and roll angles of the centrifuge. An optimization algorithm for overload simulation is proposed and verified. The algorithm minimizes the error between the simulated and expected overloads to find the optimized kinematic variables of each axis of the centrifuge. Numerical results show that: (1) the moving average algorithm substantially alleviate the abrupt changes in pitch and roll angles of the centrifuge. (2) the proposed optimization algorithm is more accurate compared to traditional algorithms.
Dynamic Simulation on Axle Box Bearing of High-Speed Train with Localized Defects under Wheel/Rail Excitation
Wang Yajia, Xin Ziting, Gu Xiaohui, Liu Yongqiang
2024,22(6):50-58, DOI: 10.6052/1672-6553-2023-112
[Abstract] (74) [HTML] (0) [PDF 1.46 M] (481)
Abstract:
Axle box bearing is a key rotating component in the bogie of high-speed trains. Under complex wheel/rail excitations, localized defects caused by fatigue, overload, etc. will threaten the operation safety of railway vehicles. In this paper, a coupled dynamic model of axle box bearing-flexible axle box-vehicle system with different bearing localized defects is established using UM/Simulation co simulation. The vibration responses of axle box with fault on outer raceway, inner raceway and roller under track irregularities and wheel ovalization are studied. In addition, the fault responses from typical points of axle box and rotary arm are compared to select the optimal mounting position of accelerometer on the axle box. The simulated results are helpful to the condition monitoring and fault diagnosis of axle box bearings in industrial applications.
Research on All-Wheel Steering Control of the Virtual Rail Train
Yang Yibo, Yang Caijin, Lu Ye, Xu Jing, Cai Liya, Zhang Weihua
2024,22(6):59-67, DOI: 10.6052/1672-6553-2023-140
[Abstract] (65) [HTML] (0) [PDF 1.42 M] (456)
Abstract:
Aiming at the steering problem of the multi-articulated virtual rail train, an all-wheel active steering control method is proposed based on the idea that the rear vehicles follow the traveling trajectory of the head one. Firstly, the traveling trajectory of the head vehicle is computed as the target path and stored in the shift register. Secondly, according to the lateral deviation of the rear axle of the vehicle from its target path, the steering angle of the rear wheel of the vehicle is determined based on the PID controller and the Stanley algorithm, and the steering angle of the front wheel of the rear vehicle is further computed using the principle of Ackermann steering geometry. Finally, the co-simulation platform of TruckSim and Matlab/Simulink is established and the simulation analysis is carried out with typical operation conditions. Obtained results show that the control method designed improves the following performance of the trailer module to the tractor module, reduces the articulation forces between the adjacent vehicles, the center-of-mass lateral deflection angle of the vehicle body and the lateral force of the tires, and thus improves the stability of the train during the steering.
The Influence of Eddy Current Braking on the Braking Dynamics Characteristics of High-Speed Trains on Straight Track
Li Jing, Zeng Mingrui, Zhang Zhibo, Xu Jiaming, Luo Jun
2024,22(6):68-79, DOI: 10.6052/1672-6553-2024-012
[Abstract] (62) [HTML] (0) [PDF 1.89 M] (453)
Abstract:
The braking performance of trains directly affects the safety, stability, and stability of vehicle operation. This article studies the impact of installing a linear track eddy current braking system on the braking dynamics characteristics of high-speed trains with different power distribution methods. Firstly, a train dynamics simulation model was established for two grouping modes, 6M2T and 4M4T, and its effectiveness was verified by comparing it with experimental data on the line. Based on this model, the dynamic characteristics of trains at different speeds under different power distribution forms were studied. The Sperling index, derailment coefficient, wheel load reduction rate, and wheel rail interaction force of the the 1st, 5th, and 8th carriages were studied for the combined braking conditions of coasting, electro-pneumatic braking, and linear track eddy current braking system. The research results showed that the dynamic force distribution method and braking system have a significant impact on the dynamic performance parameters of the vehicle, The key dynamic performance indicators involved all meet the safety limit standards, and the research results provide theoretical reference for installing a linear track eddy current braking system on high speed trains.
Modelling and Dynamic Characteristics Analysis of the Direct-Drive Electro-Mechanical Actuator
Wan Qi, Ma Shangjun, Tong Ruiting, Liu Geng
2024,22(6):80-87, DOI: 10.6052/1672-6553-2023-115
[Abstract] (56) [HTML] (0) [PDF 1.08 M] (455)
Abstract:
As a key actuator in a flight control system, the performance of an electro mechanical actuator has a significant impact on the dynamic responses of the system. Based on the structural composition of the direct drive electro mechanical actuator, a simulation model is established that considering the control of a permanent magnet synchronous motor and nonlinear factors of a planetary roller screw mechanism. The step responses of the system under the current vector control of “id=0” are studied. The results show that the system based on the three closed loop servo control strategy of the PMSM has the good dynamic performance under different position commands with the step signal. With the comparison to the literature, it is shown that the proposed simulation model of the electro mechanical actuator under this control strategy is effective.
Dissipation Characteristics and Parameter Identification of Metal Rubber Vibration Isolation Structure in Thermal Environment
Wu Yi, Zhao Yonghui, Huang Rui, Liu Haojie
2024,22(6):88-97, DOI: 10.6052/1672-6553-2023-116
[Abstract] (62) [HTML] (0) [PDF 1.48 M] (456)
Abstract:
Due to its sensitivity to temperature and the significant influence on vibration isolation performance, it is crucial to investigate the dissipation characteristic and parameter identification of metal rubber vibration isolation structure in thermal environments. In this study, a dual-layer metal rubber vibration isolation structure is designed. The influence of environmental temperature on the dissipation characteristic of the isolation structure is investigated. A nonlinear constitutive model for the dual-layer metal rubber isolation structure is established. At first, a series of dissipation characteristic tests are conducted on the isolation structure at different temperatures. Dissipation characteristic curves of the isolation structure under various operating conditions are obtained. The dissipation coefficient, dissipated energy, and maximum deformation potential energy are calculated. The effects of temperature, amplitude, and frequency on the dissipation characteristic of the dual-layer metal rubber isolation structure are analyzed. Then, the parameters of the isolation structure are identified using nonlinear least squares method. A nonlinear functional constitutive model for the metal rubber isolation structure is established. It can accurately predict the dissipation characteristic curves of the isolation structure under different operating conditions.

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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] (2986) [HTML] (0) [PDF 748.46 K] (6939)
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.
Advances and challenges in dynamics of flexible multibody systems
Tian Qiang, Liu Cheng, Li Pei, Hu Haiyan
2017,15(5):385-405, DOI: 10.6052/1672-6553-2017-039
[Abstract] (1826) [HTML] (0) [PDF 1.91 M] (6650)
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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.
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] (2932) [HTML] (0) [PDF 1.13 M] (6630)
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.
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] (2436) [HTML] (0) [PDF 1.07 M] (6255)
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.
Stochastic response surface based sensitivity analysis of uncertain parameters
Fang Shengen, Zhang Qiuhu, Lin Youqin, Zhang Xiaohua
2015,13(5):361-366, DOI: 10.6052/1672-6553-2014-064
[Abstract] (1192) [HTML] (0) [PDF 826.19 K] (6108)
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.
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] (2343) [HTML] (0) [PDF 1.87 M] (5975)
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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.
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] (2353) [HTML] (0) [PDF 1.38 M] (5856)
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.
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] (3230) [HTML] (0) [PDF 336.30 K] (5632)
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.
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] (2278) [HTML] (0) [PDF 530.95 K] (5517)
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.
Dynamics of tethered satellite system based on nonlinear unit model
Liu Zhuangzhuang, BaoYin Hexi
2012,10(1):21-26, DOI:
[Abstract] (822) [HTML] (0) [PDF 567.09 K] (5477)
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.
Research on modeling and simulation of PMSM variable frequency speed regulating system
Zhang Chen, Jin Tao
2014,12(2):183-187, DOI: 10.6052/1672-6553-2014-025
[Abstract] (1290) [HTML] (0) [PDF 811.52 K] (5303)
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.
Stable region of the feedback gainsin a controlled system with delayed feedback
Wang Jingxiang, Wang Zaihua
2008,6(4):301-306, DOI:
[Abstract] (1157) [HTML] (0) [PDF 0.00 Byte] (5259)
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.
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] (2029) [HTML] (0) [PDF 467.15 K] (4753)
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.
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] (2919) [HTML] (0) [PDF 479.50 K] (4697)
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.
Study on deeoupled engine mounting system
Li Zhiqiang, Chen Shuxun, Wei Qifeng
2013,11(4):357-362, DOI: 10.6052/1672-6553-2013-041
[Abstract] (1351) [HTML] (0) [PDF 350.50 K] (4582)
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.
Reseach of the LuGre dynamic tire model based on ADAMS/MATLAB co-simulation
Zheng Wengang, Lu Yongjie, Chen Enli, Li Shaohua
2016,14(3):247-252, DOI: 10.6052/1672-6553-2015-052
[Abstract] (1745) [HTML] (0) [PDF 2.18 M] (4561)
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.
Dynamic response calculation of a aero-engine's dual-rotor system
Zhang Huan, Chen Yushu
2014,12(1):36-43, DOI: 10.6052/1672-6553-2013-110
[Abstract] (2032) [HTML] (0) [PDF 2.22 M] (4374)
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.
Multi-objective topology optimization design method based on penalized density theory for aircraft lifting-surface
Miao Xiaoting, Xu Quan, Liu Guang, Zhang Fenggang
2014,12(3):253-258, DOI: 10.6052/1672-6553-2014-056
[Abstract] (1958) [HTML] (0) [PDF 1.00 M] (4232)
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.
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] (2104) [HTML] (0) [PDF 296.79 K] (3986)
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.
Spline finite point method for analyzing the effect of dead loads on natural frequencies of arch
Kang Ting, Xu Jinyu, Bai Yingsheng, Sun Huixiang, Li Qing
2014,12(1):62-66, DOI: 10.6052/1672-6553-2013-097
[Abstract] (1477) [HTML] (0) [PDF 832.87 K] (3893)
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.