Dynamic Behavior of Different Wheel Profiles and Their Sensitivities to Track Characteristics

2007 ◽  
Author(s):  
Asghar Nasr ◽  
Mahdi Mehrgou
Keyword(s):  
Dynamic Behavior ◽  
Ride Comfort ◽  
Dynamic Interaction ◽  
Transportation Systems ◽  
Rail Transportation ◽  
Railroad Vehicles

Wheel/rail interaction and the relevant phenomena have been of much concern to many railways and researchers during last two or three decades. On going research is being conducted for optimizing interaction between wheel and track. Safety, comfort and economical aspects in rail transportation systems are the very most common research interests in rail transportation systems. The attempts made to increase both the speed and axle load of new railroad vehicles have been the main incentives of the current progressive research in rail industries. Several strategies have been implemented and are still in use by railroad agencies to control the wear of wheels and rails and to enhance safety and ride comfort. Optimizing contact characteristics of wheel and rail using the most compatible wheel and rail profiles is an important issue concerning dynamic interaction of wheel and rail. In this paper, the effect of S1002, IR1002 and P8 wheel profiles on the interaction of wheel and rail for similar track conditions are considered.

Effect of unsupported sleepers on dynamic behavior of running vehicles and ride comfort index

2021 ◽  
pp. 095440622198937
Author(s):  
Mojtaba Azizi ◽  
Majid Shahravi ◽  
Jabbar-Ali Zakeri
Keyword(s):  
Numerical Model ◽  
Dynamic Behavior ◽  
Multibody Dynamics ◽  
Field Test ◽  
Ride Comfort ◽  
Vehicle Speed ◽  
Comfort Index ◽  
Railway Industry ◽  
Flexible Track ◽  
Train Speed

Nowadays, with various advancements in the railway industry and increasing speed of trains, the design of railway tracks and vehicles has become vitally important. One of the frequent problems of ballasted tracks is the existence of unsupported sleepers. This phenomenon occurs due to the lack of ballast underneath the sleepers. Here, a model is presented, in which a flexible track model in a multibody dynamics program is developed, in order to study the dynamic behavior of a vehicle. By utilizing the model, it is feasible to simulate unsupported sleepers on the flexible track including rail, sleeper, and ballast components. In order to verify the results of numerical model, a field test is performed. Findings indicate that, in the case of a single unsupported sleeper through the track, the ride comfort index increased by 100% after increasing the train speed from 30 to 110 km/h. Moreover, when it is needed to have ride comfort index improvement over the uncomfortable level, the vehicle speed should be less than 70 km/h and 50 km/h for tracks with one unsupported sleeper and two unsupported sleepers, respectively.

Utilization of adaptive methodology to underpin rail transportation systems: Sydney metro’s methodical formulation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Koorosh Gharehbaghi ◽  
Kerry McManus ◽  
Matt Myers
Keyword(s):  
Complex System ◽  
Triple Bottom Line ◽  
Transportation Systems ◽  
System Thinking ◽  
Rail Transportation ◽  
Bottom Line ◽  
Content Type ◽  
Transportation Projects ◽  
Separate Dimension

Purpose As a part of adaptive and complex system thinking, geographic information systems (GIS) are beneficial particularly for transportation projects, where uncertainty is frequent. Accordingly, this paper aims to examine the utilization of GIS in line with adaptive and complex system thinking, as the basis of the methodical formulation of perceived gaps within the integrated transportation planning (ITP) specifically for the mega transportation projects. Such a framework is undertaken, as the mega transportation projects although may seem straightforward, however, are problematic and require more consideration than the traditional triple bottom line factors. Using the Sydney Metro as the case study, the outcome demonstrates the significance of the fourth separate dimension of engineering into the aforementioned bottom-line factors. Design/methodology/approach The research examines the utilization of adaptive and complex system thinking, as the basis of the methodical formulation of perceived gaps within the ITP. The use of Sydney’s Metro project is a novel example of the proposed methodical formulation and its empirical assessment and provides a better understanding of the use of mapping and planning tools for mega transportation projects. Findings Aptly, using the developed conceptual framework, this research further validates the inclusion of a separate engineering dimension with the usual triple bottom line factors. Such inclusion is paramount in responding to the existing ITP gaps found within the current literature. Originality/value This research uses GIS and ITP process to support the aforementioned adaptive and complex system thinking. This, in turn, is used as the basis of a methodical formulation framework in dealing with mega rail transportation infrastructure. To support such a proposition, Sydney Metro is examined as the basis of a case study.

Assessing the Existing Bursa Light Rail Transportation System

2020 ◽  
Vol 2674 (10) ◽  
pp. 250-260
Author(s):  
Mehmet Rizelioğlu ◽  
Turan Arslan
Keyword(s):  
Traffic Congestion ◽  
Transportation System ◽  
Transportation Systems ◽  
Bus Rapid Transit ◽  
Light Rail ◽  
Rail Transportation ◽  
Transit System ◽  
Transit Systems ◽  
Negative Impacts

As car ownership soars, traffic congestion and its associated negative impacts have become real concerns in many cities around the world. Therefore, transportation systems that perform better in eliminating or reducing traffic congestion and related problems to tolerable levels have become imperative. Alternative transit systems should be assessed properly to accommodate the expected demand in the long term, at least, to some significant extent. However, this is generally neglected in developing countries and, among many possible alternatives, a popular transportation system is usually preferred within the available budget. As an example, Bursa Metropolitan Municipality, Turkey, has recently implemented a light rail transportation system (LRT) on its major east–west corridor as the main transit system. In this study, the existing LRT is assessed and its performance is compared with a hypothetical bus rapid transit (BRT) system, which is a strong contender and comparatively a lower-cost alternative. This is done to assess whether the LRT was the better choice in relation to the current demand. Therefore, in this study, the existing LRT system is first defined in the PTV VISSIM simulation environment. Then, the hypothetical BRT system is considered on the same route with the current demand. The capability and capacities of the existing LRT and the BRT system are assessed and compared in many aspects. The results are compared, and important findings are outlined.

Dynamic Interaction Between a Straight Tube and an Anti-Vibration Bar

2009 ◽  
Author(s):  
Isabelle Nowlan ◽  
Annie Ross ◽  
Michel J. Pettigrew
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Interaction ◽  
Plane Motion ◽  
Work Rate ◽  
Fretting Wear ◽  
Straight Tube ◽  
Local Excitation ◽  
Out Of Plane ◽  
Simple Supports ◽  
Excitation Force

Fretting-wear is a known problem in steam generator U-tubes. These tubes are supported by flat bars called anti-vibration bars (AVB) in the plane of the U-bend. Clearances between the tubes and the bars are designed to be minimal, but cumulative tolerances and manufacturing variations may lead to clearances larger than expected. Large clearances may result in ineffective support leading to in-plane and out-of-plane motion causing fretting-wear and impact abrasion. In the present work, the problem is investigated with a single two span tube, an anti-vibration bar at mid-span and a local excitation force. The dynamic behavior of a tube with simple supports at both ends and an anti-vibration bar at mid-span is characterized. The influence of clearance, preload and tilt of the support on the dynamics of the tube are investigated experimentally. The results indicate that the fretting-wear work-rate is very low with preloads, reaches a maximum around a zero clearance and diminish again for larger clearances. The tilt of the anti-vibration bar in our experiments seems to change the dynamic behavior of the tube.

Melbourne's Advanced Rail Transportation

2020 ◽  
Vol 3 (2) ◽  
pp. 24-36
Author(s):  
Koorosh Gharehbaghi ◽  
Ken Farnes ◽  
Matt Myers
Keyword(s):  
Transportation Systems ◽  
Operating Costs ◽  
Rail Transportation ◽  
Operational Flexibility ◽  
Rail Network ◽  
Optimal Decisions ◽  
Commuter Rail ◽  
Passenger Satisfaction ◽  
Selection Of

Melbourne's commuter rail transportation is ageing and outdated. As Melbourne's population is ever-increasing, its rail transportation infrastructure planning also needs to be developed, based on long-term technological advancements. Subsequently, Melbourne's rail network and its systems need to be continuously scrutinized. This study thus reviews Melbourne's advanced rail transportation systems, and determines its future perspectives. This research initially found that, for Melbourne, one of the important aspects of long-term technological innovation is the inclusion of the three specific automation measures of; moderate intrusion control systems; revamp signaling technologies; and new rail lines and systems. Further examination recommended that advanced rail transportation systems including enhanced communications systems, be carefully integrated. Such outcomes will in turn boost Melbourne's rail performance through, a) increase safety and passenger satisfaction; b) enhance system reliability; c) intensify train frequency and capacity; d) improve operational flexibility; and e) reduce the overall operating costs. It is expected that these findings will ultimately assist the relevant rail transportation planners, to make optimal decisions when deciding on the selection of the most advanced rail transportation strategies.

Experimental Study of Dynamic Interaction Between a Steam Generator Tube and an Anti-Vibration Bar

2010 ◽  
Author(s):  
V. Lalonde ◽  
A. Ross ◽  
M. J. Pettigrew ◽  
I. Nowlan
Keyword(s):  
Experimental Study ◽  
Dynamic Behavior ◽  
Steam Generator ◽  
Contact Force ◽  
Dynamic Interaction ◽  
Work Rate ◽  
Fretting Wear ◽  
Steam Generators ◽  
Simply Supported ◽  
Excitation Force

A first experimental work was previously carried out to study the dynamic behavior of a tube simply supported at both ends in interaction with an anti-vibration bar at mid-span. This paper presents modifications to the previous setup with the aim of improving the accuracy of the results. A comparison of the dynamic behavior of the tube is made between both setups. The objective of this experimental study is to characterize the vibration behavior of U-tubes found in steam generators of nuclear power plants. Indeed, two-phase cross-flow in the U-tubes section of steam generators can cause many problems related to vibration. In fact, flow-induced vibration of the U-tubes can cause impacts or rubbing of the tubes against their flat bar supports. Variation of the clearance between the AVB and the U-tubes may lead to ineffective supports. The resulting in-plane and out-of-plane motions of the tubes are causing fretting-wear and impact abrasion. In this study, the clearance between the tube and the AVB, as well as the amplitude, form and frequency of the excitation force are controlled parameters. The first two modes of the tube are studied. The modifications made to the setup lead to significant improvements in the results. The natural frequencies of both setups are compared to theoretical values. The difference between experimental and theoretical frequencies confirms that the new setup better represents the theoretical model of a simply supported tube. The damping of both setups is also compared to values found in literature. The results show that the new setup is more representative of realistic steam generator situations. Compared to the first setup, the displacements of the new setup clearly indicate that the movement of the tube is mostly parallel to the flat bar and in the same direction as the excitation force. The whirling motion of the tube is prevented in the new setup. The accuracy of the contact force as a function of clearance was also improved. The use of more sensitive force sensors helped to reduce the noise level of the contact force. Finally, the dynamic interaction between the tube and the AVB, defined by the fretting wear work-rate, presents a more consistent behavior. The maximum work-rate occurs when the tube is excited around the second mode for clearance between −0.10 and 0.00 mm. Such clearance between the tube and the AVB should then be avoided to minimize fretting damage.

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