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461.
以往动态车道研究倾向于在固定信号配时或预先设定的信号配时方案下进行优化,无法充分利用交叉口的时空资源.本文根据实时交通需求,以交叉口车辆平均延误最小为目标,以信号周期、相位绿灯时间和车道数为约束条件,构建动态车道与交通信号协同优化模型.模型分两部分,第1部分考虑进出口道车道平衡,计算可行的动态车道备选方案,将备选方案的输出参数作为第2部分模型的输入参数;第2部分根据实时交通需求,生成动态车道优化方案和信号优化方案.将本文优化方法与传统信号配时方法进行比较,实验结果表明,本文模型能更好地降低交叉口平均延误,有效提升信号交叉口时空资源利用率. 相似文献
462.
基于附加质量法,反演瑞雷波在巨粒土路基中传播的横波波速;根据横波波速和巨粒土路基强度间的相关性得到巨粒土路基的动态回弹模量,由此评价巨粒土路基的施工质量;将瑞雷波法测得回弹模量和FWD法、承载板法获得的结果比较,结果显示由瑞雷波法评价巨粒土路基的施工质量是可行的。 相似文献
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以广西钦州保税港区铁路支线为工程背景,对吹砂填海路基的强夯处理工艺和加固效果进行现场试验研究。结果表明:海底下卧淤泥层受自然沉降、砂体挤压和强夯垂直动应力多重影响,大部分淤泥被挤出,吹填砂体内孔隙水和气体被排出,土颗粒移动靠拢、土体压缩,土体固结效果好,承载力得到显著提高,大于设计要求180 kPa,加固效果满意。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(4):539-561
In this paper, vehicle stability control and fuel economy for a 4-wheel-drive hybrid vehicle are investigated. The integrated controller is designed within three layers. The first layer determines the total yaw moment and total lateral force made by using an optimal controller method to follow the desired dynamic behaviour of a vehicle. The second layer determines optimum tyre force distribution in order to optimise tyre usage and find out how the tyres should share longitudinal and lateral forces to achieve a target vehicle response under the assumption that all four wheels can be independently steered, driven, and braked. In the third layer, the active steering, wheel slip, and electrical motor torque controllers are designed. In the front axle, internal combustion engine (ICE) is coupled to an electric motor (EM). The control strategy has to determine the power distribution between ICE and EM to minimise fuel consumption and allowing the vehicle to be charge sustaining. Finally, simulations performed in MATLAB/SIMULINK environment show that the proposed structure could enhance the vehicle stability and fuel economy in different manoeuvres. 相似文献
469.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(5):547-565
In this paper, a new method is presented for estimating the current sprung mass inertial parameters of a vehicle, such as the mass, pitch and roll mass moments of inertia, and lateral and longitudinal centre of gravity locations. The method measures the sprung mass response when the vehicle is driven over an unknown and unmeasured random road profile. From these measurements, the equivalent free-decay responses are extracted and modal analysis techniques used to estimate the sprung mass natural frequencies, damping ratios and mode shapes. This information is combined with a simplified vehicle estimation model, least squares analysis and known equivalent stiffness parameters to estimate the vehicles’ inertial parameters. The results obtained from several simulation examples show that estimates of the inertial parameters generally have small relative errors. 相似文献
470.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(11):1667-1685
A two-dimensional computational model for assessment of rolling contact fatigue induced by discrete rail surface irregularities, especially in the context of so-called squats, is presented. Dynamic excitation in a wide frequency range is considered in computationally efficient time-domain simulations of high-frequency dynamic vehicle–track interaction accounting for transient non-Hertzian wheel–rail contact. Results from dynamic simulations are mapped onto a finite element model to resolve the cyclic, elastoplastic stress response in the rail. Ratcheting under multiple wheel passages is quantified. In addition, low cycle fatigue impact is quantified using the Jiang–Sehitoglu fatigue parameter. The functionality of the model is demonstrated by numerical examples. 相似文献