检索结果-南通市图书馆

ON NATURAL CHARACTERISTICS OF A RIGID MOTOR FLEXIBLE BASE DYNAMIC COUPLED SYSTEM

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2004年第2期17卷 219-221页

作者： SunYuguo SongKongjie CollegeofOpticandElectronicInformationEngineering UniversityofShanghaiforScienceandTechnologyShanghai200092China CollegeofMechanicalEnginering ShandongUniversityJinan250061China

In shipping and aircraft engineering, the vibrating motor or instrumentationis usually mounted on a non-rigid base. To apply isolation design effectively, it is necessary toinvestigate the nature vibration characteristics of the rigid motor, flexible base coupled system. Auniversal dynamic express for the coupled system is derived. A PC-based measurement solution ispresented. And the system's dynamic behavior is then investigated numerically and *** results show that a strong interaction will exist between the motor's rigid mode and theflexible base's mode when the motor's mounting frequency is close to the flexible base's firstnatural frequency. The first natural frequency of the coupled system is generally lower than themotor's rigid mode frequency. At high frequency, the flexible base's modes are the dominant modes ofthe coupled system.

关键词： vibration isolation Flexible base Natural frequency

Railway ground vibration and mitigation measures: benchmarking of best practices

在线全文

学校读者我要写书评

暂无评论

Railway Engineering Science 2022年第1期30卷 1-22页

作者： Slimane Ouakka Olivier Verlinden Georges Kouroussis Department of Theoretical Mechanics Dynamics and VibrationsFaculty of EngineeringUniversity of MonsMonsBelgium

vibration and noise aspects play a relevant role in the lifetime and comfort of urban areas and their *** the different sources,the one coming from the rail transit system will play a central concern in the following years due to its ***-borne vibration and noise assessment as well as techniques to mitigate them become key elements of the environmental impact and the global enlargement planned for the railway *** paper aims to describe and compare the different mitigation systems existing and reported in liter-ature through a comprehensive state of the art analysis providing the performance of each ***,an introduction to the ground-borne vibration and noise gen-erated from the wheel-rail contact and its propagation through the transmission path is ***,the impact and the different ways of evaluating and assessing these effects are presented,and the insertion loss indicator is ***,the different mitigation measures at different levels(vehicle,track,transmission path and receiver)are discussed by describing their possible appli-cation and their efficiency in terms of insertion ***,a summary with inputs of how it is possible to address the future of mitigation systems is reported.

关键词： Ground-borne noise and vibration Railway dynamics Urban railway vibration mitigation Insertion loss vibration isolation

Design and Analysis of a Horizontal Quasi-Zero Stiffness vibration Isolator by Combining Rolling-Ball and Disk Springs in Parallel

在线全文

学校读者我要写书评

暂无评论

Journal of Beijing Institute of Technology 2017年第4期26卷 468-476页

作者： Gaofeng Guan Dengfeng Xu Yu Zhu Qiang Li Qiang Yu School of Mechatronics Engineering University of Electronic Science and Technology of China Chengdu 611731 China State Key Lab of Tribology Tsinghua University Beijing 100084 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipment and Control Tsinghua University Beijing 100084 China School of Information Engineering Wuchang University of Technology Wuhan 430223 China

Combining disk springs having negative stiffness with a rolling-ball in parallel is proposed in this paper. It is used to reduce the system stiffness and the positioning error in a non-ideal *** characteristics of a disk spring are analyzed. The dynamic equation of its motion has been obtained based on Newton＇s second law. After definition of a error margin,the dynamic equation of the motion can be treated as a Duffing oscillator,and the influences of non-dimensional parameters on the stiffness and transmissibility are studied. The natural frequency and transmissibility are achieved in a linearization range,where the ratio of linear to nonlinear items is small *** influence of mass ratio and non-dimensional parameters on natural frequency are analyzed. Finally,a comparison of numerical example demonstrates that the QZS system can realize a lower stiffness within an increased range.

关键词： quasi-zero stiffness (QZS) vibration isolation natural frequency transmissibility

Study on the vibrational Power Flow Transmission Characteristics of Gearb ox

在线全文

学校读者我要写书评

暂无评论

厦门大学学报(自然科学版) 2002年第S1期 84-85页

作者： ZHANG Bing, SONG Kong-jie, SUN Ling-ling, QI Wen-guo (School of Mechanical Engineering, Shandong University, Jinan 250061, China)

Gearbox as an important source of noise and vibration, its structure-borne nois e has drawn more and more attentions and has become an important investigation t opic. The gearbox is extremely complicated mechanical equipment. In general, the profiles of gear teeth are not perfect. Together with the time-varying stiffne ss during tooth mesh, an in-plane force will be induced at the rim of a rotatin g gearwheel, which creates the vibration. These vibrations are transmitted throu gh the shafts, the bearings, and finally to the gearbox. At the same time, they will produce air-borne noise during tooth mesh, which radiate directly to the g earbox and through the gearbox radiate to the neighboring environment. In this paper, the overall dynamics of a gear system that includes a spur gear p air, shafts, bearings and a flexible gearbox is investigated. At first, the gear ed rotor system comprising gears, shafts, bearings and gearbox is set up and sim plified into a Source-Path-Receiver (SPR) model. Here, the rotating system inc luding the gears, shafts, primer mover and load is considered as the Source whil e the gearbox is regarded as the receiver and the bearings are treated as the Pa th. The dynamics of the SPR model is analyzed and the power flow transmitted fro m the source to the receiver is derived. Then the geared motor system is studied by finite element method (FEM), and corresponding mobility matrices are built b y choosing proper FEM model. Based on these data and the bearing’s mobility mat rix, the overall model of gearbox is developed using the component mobility meth od. At last the power flow transmission properties between substructures or subs ystem of gearbox are studied from the viewpoint of energy. The result will provi de the reliable computational foundation for improving the gearbox’s dynamical performance.

关键词： vibration isolation vibration measurement pow er flow

Effects of anti-symmetric nonlinear viscous damping on the force transmissibility of multi-degree of freedom structures

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2011年第6期1卷 63-68页

作者： Zhike Peng,1, ) and Zhiqiang Lang2 1)State Key Laboratory of Mechanical System and vibration, Shanghai Jiao Tong University, Shanghai 200240, China 2)Department of Automatic Control and Systems Engineering, University of Sheffeld Mappin Street, Sheffeld, S1 3JD, UK State Key Laboratory of Mechanical System and vibration Shanghai Jiao Tong University Shanghai 200240 China Department of Automatic Control and Systems Engineering University of Sheffield Mappin Street Sheffield S1 3JD United Kingdom

In the present study, the concept of the output frequency response function is applied to theoretically investigate the force transmissibility of multi-degree of freedom (MDOF) structures with a nonlinear anti-symmetric viscous damping. The results reveal that an anti-symmetric nonlinear viscous damping can significantly reduce the transmissibility over all resonance regions for MDOF structures while it has almost no effect on the transmissibility over non-resonant and isolation regions. The results indicate that the vibration isolators with an anti-symmetric damping characteristic have great potential to overcome the dilemma in the design of linear viscously damped vibration isolators where an increase of the damping level reduces the force transmissibility over resonant region but increases the transmissibility over non-resonant regions.

关键词： nonlinear damping force transmissibility vibration isolation volterra series

Multi Objective Robust Active vibration Control for Flexure Jointed Struts of Stewart Platforms via H∞ and μ Synthesis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2008年第2期21卷 125-133页

作者：刘磊王本利哈尔滨工业大学卫星技术研究所黑龙江哈尔滨150080

Active vibration control is needed for future space telescopes, space laser communication and other precision sensitive payloads which require ultra-quiet environments. A Stewart platform based hybrid isolator with 6 hybrid struts is the effective system for active/passive vibration isolation over 5-250 Hz band. Using an identification transfer matrix of the Stewart platform, the coupling analysis of six channels is provided. A dynamics model is derived, and the rigid mode is removed to keep the signal of pointing control. Multi objective robust H∞ and μ synthesis strategies, based on singular values and structured singular values respectively, are presented, which simultaneously satisfy the low frequency pointing and high frequency disturbance rejection requirements and take account of the model uncertainty, parametric uncertainty and sensor noise. Then, by performing robust stability test, it is shown that the two controllers are robust to the uncertainties, the robust stability margin of H, controller is less than that of μ controller, but the order of μ controller is higher than that of H, controller, so the balanced controller reduction is provided. Additionally, the μ controller is compared with a PI controller. The time domain simulation of the μ controller indicates that the two robust control strategies are effective for keeping the pointing command and isolating the harmonic and stochastic disturbances.

关键词： vibration isolation active struts Stewart platform H∞ synthesis μ synthesis rigid mode model reduction

vibration Control for Two Air Compressor Units Used in Tandem

在线全文

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2014年第4期2卷 314-321页

作者： Viorel-Mihai Nani Ioan Cires Faculty of Engineering University″Ioan Slavici″TimisoaraTimisoaraRomania Research Department SC PRO ATLAS ING SRL TimisoaraTimisoaraRomania

The paper presents the vibration control for two air compressors used in tandem to an oxygen generating station. The compressors are identical in terms of constructive and functional properties, and are both located on similar foundations. Each compressor is supported on a foundation made from one massive block of concrete, provided with some elastic and damping parts. This anti vibrating structure insulates the machines compared to other station equipment. During operation, were observed dangerous levels of vibration at one of the machines, which forced some unwanted stoppages for the station. Two hypotheses have been promoted. One of them referred to a pronounced wear of one compressor, although this was relatively new. The second hypothesis has taken in consideration the appearance of some cracks in the foundation massive concrete block. Experimental research conducted on the spot led to the identification of some errors done at foundation fabrication. The experimental results and some theoretical investigations are presented in this paper.

关键词： Foundation Harmonic Disturbing Forces Amortized Forced vibration vibration isolation Coefficient of Transmissibility

NATURAL LOGARITHM-BASED SLIDING MODE CONTROL FOR ACTIVE ENGINE MOUNT

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

NATURAL LOGARITHM-BASED SLIDING MODE CONTROL FOR ACTIVE ENGI...

Objective evaluation of engine mounting isolation

The Third International Conference on Dynamics, vibration and Control

作者： Andika Aji Wijaya Fadly J.D Wahyudi R.Akmeliawati Department of Mechatronics International Islamic University MalaysiaKuala Lumpur 50728Malaysia Department of Mechanical International Islamic University MalaysiaKuala Lumpur 50728Malaysia

＜正＞This paper discusses Natural Logarithm Sliding Mode Control（In-SMC）for active engine mounting （AEM）system to isolate engine body *** system is designed to deal with isolation of vibration in high level frequency.A number of controllers for AEM system have been *** of them is sliding mode *** there is no systematic method to determine sliding surface for conventional sliding mode technique to assure the controller able to attenuate the vibration and asymptotically *** main advantage of the proposed controller compared to the conventional（linear）sliding mode control is that the magnitude of vibration can be bounded by introducing the nonlinear sliding surface（logarithm function）.The result shows that In-SMC is not only able to attenuate the vibration but also robust to the different types of disturbance and parametric uncertainties such as mass,stiffness,and damping coefficient.

关键词： Nonlinear system natural logarithm sliding mode active engine mounting vibration isolation variable structure control

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Objective evaluation of engine mounting isolation