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661.
Jingliang Wang Chunguo Xu Guangsheng Ren Beijing Research Institute of M./E. Technology Beijing China 《上海交通大学学报(英文版)》2000,(1)
ThepaperwassponsoredbyPanDengBprojectIntroductionThecrosswedgerollingprocesshasmnyadVatages.ItisaldndofneweffectiveandeconomictechnologythatProducesstePPedshaft.ThetOchnologyhowtoimPovetheaccuracyofworkPiecehasbeingdeVeoped.ThediametertoleraneofsolidpartscanbelimitedbetWeen0.2mmto0.5mm.Thelengthtolerancerangedbforeen0.2nuntolmm.TheaccuracyofpatscouldsatsfythePfOcisionlevelofthetoleranceandmachiningallowancesofsteeldieforeingChinesenationalstandard.[l]Butthediametertoleranceofhollowpeds… 相似文献
662.
雾封层在河惠高速公路预防性养护中的应用 总被引:7,自引:0,他引:7
通过对河惠高速公路采用雾封层措施的沥青路面预防性养护工程,施工前后的路面性能进行检测以及数据对比评价雾封层措施的效果,表明雾封层措施能有效的改善路面表观性能,抑制病害对道路的结构损害,起到延长道路寿命的作用. 相似文献
663.
S. Cardona E. Fern ndez-Dí az M. A. Santos J. L. Tejedo 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,33(6):421-434
In this paper we present a simple model for the time history of the vibrations generated by a running underground train at a measuring point on the wall of a tunnel. The experimental data will be fitted to the model. As a result, a set of model parameters representative of the general maintenance condition of the bogies of the train will be estimated. Our work seeks to help the staff of metropolitan railways in charge of vibration control decide when to turn the wheels of their trains on a lathe. 相似文献
664.
Cooperative adaptive cruise control (CACC) systems are a candidate to improve highway capacity by shortening headways and attenuating traffic disturbances. Although encouraging results have been obtained until now, a wide range of traffic circumstances has to be investigated in order to get reliable CACC systems driving on real roads. Among them, handling both vehicle-to-vehicle (V2V) communications-equipped and unequipped vehicles merging into the string of CACC vehicles is a commonly mentioned challenge. In this article, an algorithm for managing the transitions in response to cut-ins from V2V- or non-V2V-equipped vehicles is developed and tested using a string of four CACC vehicles. A CACC controller is implemented in four production Infiniti M56s vehicles and tested in real traffic, where non-V2V-equipped vehicles can cut in. The effects of a vehicle performing a cut-out are also investigated. Then responses to cut-ins by equipped and nonequipped vehicles are simulated for longer strings of vehicles using car-following models for both the production adaptive cruise control (ACC) system and the newly developed CACC controller. Results demonstrate that the CACC system is able to handle cut-in vehicles without causing major perturbations, while also reducing significantly the impact of this maneuver on the following vehicles, improving traffic flow. 相似文献
665.
I. Youn M. A. Khan N. Uddin E. Youn M. Tomizuka 《International Journal of Automotive Technology》2017,18(2):307-316
This research investigates stochastic estimation of a look-ahead sensor scheme using the optimal preview control for an active suspension system of a full tracked vehicle (FTV). In this scheme, wheel disturbance input to the front wheels are estimated using the dynamic equations of the system. The estimated road disturbance input at the front wheels are utilized as preview information for the control of subsequently following wheels of FTV. The design of optimal preview control is used as a classical linear quadratic Gaussian problem by combining dynamics of the original system and estimation of previewed road inputs. The effectiveness of the preview controller is evaluated by comparing the estimated information with the measured information for different road profiles, where Kalman filter is used for the state-variables estimation of the FTV. This research also considers the reduced order estimation using commonly available sensors in order to decrease the number of sensors and measurements. The simulation results’ using an active suspension system with different preview information shows that the proposed system can be beneficial for the improvement of ride comfort of tracked vehicles without using any specialized sensors for preview information calculation. 相似文献
666.
盾构管片接头是整环管片力学性能的薄弱部位,容易发生破坏。通过分析盾构管片接头的受力特性、管片接头的破坏类型以及管片内力和其影响因素之间的关系,再进行人工神经网络敏感性分析,计算得到不同影响因素的相对重要性指数大小。研究结果表明:盾构管片接头的破坏类型为受拉破坏;管片外径(RI=54.4%)对管片最大拉应力影响最大,其次是围岩等级(RI=35.3%),隧道埋深和混凝土强度对管片最大拉应力影响较小,相对重要性指数RI小于6%。 相似文献
667.
分析了铁路沿线居民对噪声的反应,并比较了铁路与交通运输噪声主观反应。结果表明,无论是高干扰率阈值的比较,或是从高干拢率与声级的回归方程比较,铁路和交通这两种运输噪声对人的主观反应干扰基本一样。 相似文献
668.
R. Conti E. Galardi E. Meli D. Nocciolini A. Rindi 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(5):651-671
Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components. 相似文献
669.
670.
An Alternative Method to Determine the Magic Tyre Model Parameters Using Genetic Algorithms 总被引:2,自引:0,他引:2
J. A. Cabrera A. Ortiz E. Carabias A. Simon 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2004,41(2):109-127
Summary Tyre behavior plays an important role in vehicle dynamics research. Knowledge of tyre properties is necessary to properly design vehicle components and advance control system. For that purpose mathematical models of the tyre are being used in vehicle simulation models. The Magic Formula Tyre Model is a semi-empirical tyre model which describes tyre behavior quite accurately. The Magic Formula Tyre Model needs a set of parameters to describe the tyre properties; the determination of these parameters is dealt with in this paper. A new method based on genetic techniques is used to determine these parameters. The main advantages of the method are its simplicity of implementation and its fast convergence to optimal solution, with no need of deep knowledge of the searching space. So to start the search, it is not necessary to know a set of starting values of the Magic Formula parameters. The comparison between analytical optimization methods and the method proposed is discussed in this paper. 相似文献