期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
Derailment risk and dynamics of railway vehicles in curved tracks: Analysis of the effect of failed fasteners 被引量:4
1
作者 Silvia Morales-Ivorra Julia Irene Real +1 位作者 Cesar Hernandez Laura Montalbain 《Journal of Modern Transportation》 2016年第1期38-47,共10页
The effect of the fastener's failure in a railway track on the dynamic forces produced in the wheel-rail contact is studied using the simulation software VAMPIRE to assess the derailment risk of two different vehicle... The effect of the fastener's failure in a railway track on the dynamic forces produced in the wheel-rail contact is studied using the simulation software VAMPIRE to assess the derailment risk of two different vehicles in two curves with distinct characteristics. First, a 3D-FEM model of a real track is constructed, paying special attention to fasteners, and calibrated with displacement data obtained experimentally during a train passage. This numerical model is subsequently used to determine the track vertical and lateral stiffness. This study evidences that although the track can practically lose its lateral stiffness as a consequence of the failure of 7 consecutive fasteners, the vehicle stability would not be necessarily compromised in the flawed zone. Moreover, the results reveal that the uncompensated acceleration and the distance along which the fasteners are failed play an important role in the dynamic behavior of the vehicle-track system, influencing strongly the risk of derailment. 展开更多
关键词 Railway dynamics Fasteners Derailment curved track
下载PDF
Performance Analysis of Curved Track G2T-FSO(Ground-to-Train Free Space Optical)Model under Various Weather Conditions
2
作者 Mohammed A.Alhartomi Mohammad F.L.Abdullah +5 位作者 Wafi A.B.Mabrouk Mohammed S.M.Gismalla Ahmed Alzahmi Saeed Alzahrani Mohammad R.Altimania Mohammed S.Alsawat 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第12期2087-2105,共19页
The demand for broadband data services on high-speed trains is rapidly growing as more people commute between their homes and workplaces.However,current radio frequency(RF)technology cannot adequately meet this demand... The demand for broadband data services on high-speed trains is rapidly growing as more people commute between their homes and workplaces.However,current radio frequency(RF)technology cannot adequately meet this demand.In order to address the bandwidth constraint,a technique known as free space optics(FSO)has been proposed.This paper presents a mathematical derivation and formulation of curve track G2T-FSO(Ground-to-train Free Space Optical)model,where the track radius characteristics is 2667 m,divergence angle track is 1.5°for train velocity at V=250 km/h.Multiple transmitter configurations are proposed to maximize coverage range and enhance curve track G2T-FSO link performance under varying weather conditions.The curved track G2T-FSO model was evaluated in terms of received power,signal-to-noise ratio(SNR),bit error rate(BER),and eye diagrams.The results showed maximum coverage lengths of 618,505,365,and 240 m for 4Tx/1Rx,3Tx/1Rx,2Tx/1Rx,and 1Tx/1Rx configurations,respectively.The analyzed results demonstrate that the G2T-FSO link can be effectively implemented under various weather conditions. 展开更多
关键词 Free space optics curve track ground-to-train communications geometrical loss weather conditions
下载PDF
Analysis of the Lateral Stability of a Truck on the NRC Curved Track Simulator
3
作者 DukkipatiRaoV 《Journal of Modern Transportation》 1994年第2期126-137,共12页
The development of experimental facilities for rail vehicle testing at the NRCCentre for Surface Transportation Technology is being complemented byanalytic studies. The purpose of this effort has been to gain insight ... The development of experimental facilities for rail vehicle testing at the NRCCentre for Surface Transportation Technology is being complemented byanalytic studies. The purpose of this effort has been to gain insight into thedynamics of rail vehicles in order to guide the development of the Curved TrackSimulator (CTS) and to establish an analytic framework for the design andinterpretation of tests to be conducted on the CTS. The work described hererepresents an initial effort towarde meeting these objectives.Parametric study results using linear model of freight truck on the CTSshowed that (a) increasing roller radius increases critical speed (b) increasingthe wheel initial cone angle will decrease the hunting speed (c) increasing theroller cant increases hunting speed (d) decrowning of the wheelset on the rollerewill not effect the hunting speed but induces longitudinal destabilzing horizontalforces at the contact and (e) lozenging of wheelset on the rollers induces a yawmoment and the hunting speed decreases with increasing wheelset yaw angle. 展开更多
关键词 TRUCK curved track SIMULATOR TRANSPORTATION lateral stability
下载PDF
Analytical study on the dynamic displacement response of a curved track subjected to moving loads 被引量:4
4
作者 Ke-fei LI Wei-ning LIU +1 位作者 Valeri MARKINE Zhi-wei HAN 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2013年第12期867-879,共13页
A closed-form out-of-plane dynamic displacement response of a curved track subjected to moving loads was proposed.The track structure was modeled as a planar curved Timoshenko beam periodically supported by the double... A closed-form out-of-plane dynamic displacement response of a curved track subjected to moving loads was proposed.The track structure was modeled as a planar curved Timoshenko beam periodically supported by the double-layer spring-damping elements.The general dynamic displacement response induced by the moving loads along the curve on the elastic semi-infinite space was firstly obtained in the frequency domain,according to the Duhamel integral and the dynamic reciprocity theorem.In the case of the periodic curved track structure subjected to moving loads,the dynamic displacement equation was simplified into a form of summation within the basic track cell instead of the integral.The transfer function for the curved track was expressed in the form of a transfer matrix.Single and series moving loads were involved in the calculation program.For the verification of the analytical model,the mid-span vertical deflection of a simply support curved beam subjected to moving load was recalculated and compared with the same case in the reference.The research results indicate that:under the same moving loads,the displacement response of the curved track decreases slightly with the increasing track radius,and the displacement response of the curved track with the radius greater than or equal to 600 m is almost equivalent to the displacement response of the straight track;the frequency spectrum of the curved track is more abundant than that of the straight track,which may result in more wheel-rail resonance and rail corrugation in the curved lines. 展开更多
关键词 curved track Moving loads Dynamic displacement Analytical solution Transfer function
原文传递
Reduced-order modeling of train-curved-slab-track dynamics with the effects of fastening failures 被引量:1
5
作者 Yan Xu Zhendong Liu +4 位作者 Caijin Yang Weihua Zhang Weidong Zhu Sebastian Stichel Xiaoying Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第9期101-116,共16页
Fastening failures have frequently been found on China high-speed railway curved tracks in recent years.Thus the influence of fastening failures on high-speed train-track interaction in curved track needs to be analyz... Fastening failures have frequently been found on China high-speed railway curved tracks in recent years.Thus the influence of fastening failures on high-speed train-track interaction in curved track needs to be analyzed.A train-curved slab track interaction model is built,in which the real shape of the curved rail is considered and modeled with reduced beam model(RBM)and curved beam theory,and the slabs are modeled with four-nodes Kirchhoff-Love plate elements.The present model is validated at first with different traditional models.Then the influence of fastening failure in curved slab track on train-track interaction dynamics is studied.A different number of failed fastenings is assumed to occur at the curved track,and different types of fastening failure including the fatigue fracture of the clip structure and failure of the rail pad are considered.Based on the calculation results,the fatigue fracture of the clip structure has little influence on train-track interaction dynamics.But when rail pad failure happens and its equivalent vertical stiffness and damping are less than one-tenth of its original,the fastening failure seriously affects the high-speed train operation safety,and it must be prevented. 展开更多
关键词 Fastening failure Train-track interaction Reduced beam model curved track Train operational safety
原文传递
Progress on wheel-rail dynamic performance of railway curve negotiation 被引量:15
6
作者 Kaiyun Wang Chao Huang +2 位作者 Wanming Zhai Pengfei Liu Shen Wang 《Journal of Traffic and Transportation Engineering(English Edition)》 2014年第3期209-220,共12页
Recent advances on wheel-rail dynamic performance of curve negotiation are reviewed in this paper. There are four issues, the mechanism and calculation method of curve negotiation, the analysis and assessment of dynam... Recent advances on wheel-rail dynamic performance of curve negotiation are reviewed in this paper. There are four issues, the mechanism and calculation method of curve negotiation, the analysis and assessment of dynamic performance of vehicle, the effect of vehicle parameters on dynamic performance, and the influence of railway parameters on dynamic performance. The promising future development of wheel-rail coupled dynamics theory is analyzed in the research of curve negotiation. The framework and technique matching performance of wheel-rail dynamic interaction on the curved track are put forward for modem railways. In addition, the application of performance matching technique is introduced to the dynamic engineering, in which the wheel load is reduced obviously when the speed of train is raised to 200-250 km/h. 展开更多
关键词 RAILWAY curved track dynamic interaction wheel-rail system performance matching
原文传递
Effect of High-Frequency Vertical Vibration of Track on Formation and Evolution of Corrugations 被引量:2
7
作者 金学松 温泽峰 +1 位作者 王开云 张卫华 《Tsinghua Science and Technology》 SCIE EI CAS 2004年第3期274-280,共7页
The effect of high-frequency curved track vibrations in the vertical direction on the formation and development of rail corrugation was analyzed. Kalker抯 non-Hertzian rolling contact theory was modified and used to c... The effect of high-frequency curved track vibrations in the vertical direction on the formation and development of rail corrugation was analyzed. Kalker抯 non-Hertzian rolling contact theory was modified and used to calculate the frictional work density on the contact area of the wheel and rail in rolling when a wheelset is steadily curving. The material loss unit area was assumed to be proportional to the frictional work density to determine the wear depth of the contact surface of the rail. The combined influences of the corrugation and the coupled dynamics of the railway vehicle and track were taken into consideration in the numerical simulation. For simplicity, the model considered one fourth of freight car without lateral motion, namely, a wheelset and the equivalent one fourth freight car body above it. The Euler beam was used to model the rails with the track structure under the rails replaced with equivalent springs, dumpers, and mass bodies. The numerical results show that the high-frequency track vibration causes formation of the initial corrugation on the smooth contact surface of the rail when a wheelset is steadily curving. The corrugation wave length depends on the frequencies and the rolling speed of the wheelset. The vibration frequencies also affect the depth and increase the corrugation. 展开更多
关键词 rail corrugation curved track high-frequency vibration rolling contact frictional work vehicle dynamics
原文传递
HOMOTOPY CURVE TRACKING FOR TOTAL VARIATION IMAGE RESTORATION 被引量:1
8
作者 Penlin Yang Ke Chen Bo Yu 《Journal of Computational Mathematics》 SCIE CSCD 2012年第2期177-196,共20页
The total variation (TV) minimization problem is widely studied in image restora- tion. Although many alternative methods have been proposed for its solution, the Newton method remains not usable for the primal form... The total variation (TV) minimization problem is widely studied in image restora- tion. Although many alternative methods have been proposed for its solution, the Newton method remains not usable for the primal formulation due to no convergence. A previous study by Chan, Zhou and Chan [15] considered a regularization parameter continuation idea to increase the domain of convergence of the Newton method with some success but no robust parameter selection schemes. In this paper, we consider a homotopy method for the same primal TV formulation and propose to use curve tracking to select the regular- ization parameter adaptively. It turns out that this idea helps to improve substantially the previous work in efficiently solving the TV Euler-Lagrange equation. The same idea is also considered for the two other methods as well as the deblurring problem, again with improvements obtained. Numerical experiments show that our new methods are robust and fast for image restoration, even for images with large noisy-to-signal ratio.Mathematics subject classification: 65N06, 65B99. 展开更多
关键词 Image restoration Total variation Newton method Homotopy method Cor-rection and curve tracking.
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部