Browse Topic: High-speed rail systems

Items (35)

Evaluation of Friction Torque in Tapered Roller Bearings

2024-01-3047

09/08/2024

A bearing is a mechanical component that transmits rotation and supports load. Depending on the type of rotating mechanism, bearings are categorized into ball bearings and tapered-roller bearings. Tapered-roller bearings are superior to ball bearings in load-bearing capabilities. They are used in applications where high loads, such as, the wheel bearings for commercial vehicles and trucks, aircraft, high-speed trains, and heavy-duty spindles for heavy machinery must be supported. The demand for reducing the friction torque in automobiles has recently increased owing to carbon-emission regulations and fuel-efficiency requirements. Therefore, research on the friction torque of bearings is essential; studies have been conducted on lubrication, friction, and contact in tapered-roller bearings. There have also been studies on lip friction, roller misalignment, and so on; however, research on the influence of roller geometries and material properties is scarce. This study investigated the

Lee, Seungpyo, An, Hyun Gyu

Using an Inerter-Based Suspension to Reduce Carbody Flexible Vibration and Improve Riding-Comfort

10-07-02-0009

02/01/2023

The riding-comfort of high-speed trains affects the travel experience of passengers, and the lightweight design technology of the carbody increases the flexible vibration and reduces passenger comfort. To this end, a vertical dynamics model of railway vehicles is established to demonstrate the potential of using passive inerter-based suspensions to reduce the flexible vibration of the carbody and improve riding-comfort. According to the characteristics of the inerter component, an appropriate inerter-based suspension is applied to the railway vehicle to reduce low-frequency resonance. The sum of the comfort indexes of the three reference points of the carbody is optimized as the objective function to improve the passenger comfort of the whole vehicle. The results reveal that the inerter-based suspension applied to the primary or secondary suspension has different effects on vehicle vibration. Compared with the traditional suspension, the riding-comfort using the inerter in both the

He, X.L., Chen, J., Tang, D. Y., Peng, S., Tang, B.B.

Improving Overhead Equipment Devices for a New Era of Railway Transportation

TBMG-40014

10/01/2021

The railway network is the backbone of the transportation system in India, connecting remote villages and towns with metropolitan cities across the country. Recent government initiatives aim to revamp and modernize the entire network by 2030 and the past couple of years have brought many changes to the rail system

Aerodynamic Performance of Different Metro Train Geometries through a Straight Tunnel Based on Steady and Unsteady Reynolds-Averaged Navier-Stokes Modeling

2020-01-5068

07/31/2020

Numerical RANS modeling has been carried out to assess the aerodynamics of different metro train geometries through a straight tunnel. A steady-state approach was first used to choose the best geometry out of seven alternatives in terms of drag reduction when compared with a typical blunt face train design representative of European metro networks. The proposed models have different edge-rounding characteristics at the front and rear faces. Afterward, the baseline and optimized geometries are compared at different train velocities, and the flow structure surrounding the models is discussed using unsteady RANS results. The study focuses on skin and pressure drag coefficients for trains traveling at 40 km h−1 in a straight tunnel with a blockage ratio of 0.69. All the considered alternatives show a drag reduction between 5% and 20% relative to the baseline case

Croquer, Sergio, Fellouah, Hachimi, Poncet, Sébastien

Detection Method for Cavity Defects in Ballastless Track Structures of High-Speed Railways Based on Air-Coupled Ultrasonic Lamb Waves

10-03-02-0010

07/02/2019

This study proposes a method for the rapid detection and location of cavity defects in ballastless track structures of high-speed railways in service. First, the propagation of air-coupled ultrasonic Lamb waves in the ballastless track structure is studied. Theoretical calculation results show that the ultrasonic Lamb wave group velocity of the A2 mode in the track plate is 4000 m/s. Then, the excitation and reception methods of the air-coupled ultrasound are studied. Theoretical and experimental results show that the A2 mode Lamb wave can be generated by the 3.8° oblique incidence of the ballastless track structure. Finally, an experimental system for air-coupled ultrasonic testing is constructed. A pair of air-coupled ultrasonic probes is used to provide excitation and reception Lamb wave signals at an inclined angle of 3.8°, 20 mm away from the surface of the track plate, and 40 mm/step along the scanning direction. Experimental data indicate that interaction between the Lamb wave

Wenfa, Zhu, Wei, Shao, Xingjie, Chen, Xiangzhen, Meng, Haiyan, Zhang

Impact of Dynamic Characteristics of Wheel-Rail Coupling on Rail Corrugation

10-03-02-0009

07/02/2019

To gain a better understanding of the characteristics of corrugation, including the development and propagation of corrugation, and impact of vehicle and track dynamics, a computational model was established, taking into account the nonlinearity of vehicle-track coupling. The model assumes a fixed train speed of 300 km/h and accounts for vertical interaction force components and rail wear effect. Site measurements were used to validate the numerical model. Computational results show that (1) Wheel polygonalisation corresponding to excitation frequency of 545-572 Hz was mainly attributed to track irregularity and uneven stiffness of under-rail supports, which in turn leads to vibration modes of the bogie and axle system in the frequency range of 500-600 Hz, aggregating wheel wear. (2) The peak response frequency of rail of the non-ballasted track coincides with the excitation frequency of wheel-rail coupling; the resonance results in larger wear amplitude of the rail. The track lateral

Gao, Xiaogang, Wang, Anbin, Gu, Xiaohan, Li, Wei

3D Design and Surface Mapping of Disc Brake Pad for High Speed Train Using FEA

2018-01-0841

04/03/2018

Recurrently, the increase in production of high-speed trains worldwide has become a confirmed fact. Seeking to use the high-speed trains locally to link the capital of Egypt “Cairo” with the new industrial cities has become a national requirement. Modeling 3D surface maps using finite element analysis (FEA) is one of the most important mechanical design tools for frictional parts to facilitate the manufacture of brake systems for heavy duty vehicles, especially high-speed trains due to difficult working conditions. In this paper, we presented simulate 3D surface maps for proposed frictional material pad using FEA at certain design parameters and experimental result conductions. The typical surface characteristics of disc brake pad are compared with commonly used materials in railway and vehicle brakes in Egypt. The surface mapping of the pad materials are characterized by the analysis and distribution for profile deformation, stress as well as the thermal distribution at different

Ali, Salah H. R., Azzam, Badr S N, Osman, Tarek, Moustafa, Ahmed

Biomimetics: nature leads the way on design

16MEIP06_1806/01/2016

That bird flight inspired Leonardo da Vinci to conceptualize “flying machines,” only to be developed centuries later by the Wright brothers by observing pigeons in flight, is quite well known. Such imitation of the models, systems, and elements of nature for the purpose of solving complex problems, otherwise known as biomimetics or biomimicry, is not new. Mother Nature is a great engineer that over the years has fascinated engineers and scientists alike, who have borrowed and applied its time-tested patterns and strategies. Technological advancements and continuous endeavors to push the limits of engineering have led to transformational innovations, as can be seen in some of the recent trends to catch up with nature's best assets. Velcro is perhaps the best known and commercially successful example of a nature-inspired design. After a hunting trip in the Alps in 1941, Swiss engineer Mestral's socks and dog were covered in burdock burrs. Intrigued by it, Mestral studied them under a

Setting the standard

15AUTP02_0402/01/2015

Meggitt CTO Emeritus begins term at helm of SAE International, seeks to encourage cross-sector relations, elevate image of SAE as aerospace industry leader. Providing leadership for a diverse organization is nothing new to Richard Greaves, Ph.D., SAE International's President for 2015. Prior to his semi-retirement in 2012, Greaves oversaw all of engineering and technology for Meggitt PLC, which specializes in aerospace equipment and has 11,000 employees operating at more than 40 sites worldwide. Now as Chief Technology Officer (CTO) Emeritus, Greaves oversees new technology for the $2.5 billion engineering business. Headquartered in the U.K., Meggitt is organized into five operating divisions-Meggitt Aircraft Braking Systems, Meggitt Control Systems, Meggitt Equipment Group, Meggitt Polymers and Composites, and Meggitt Sensing Systems-and generates revenues in excess of $2.5 billion per year. Customers include many of the major aircraft OEMs and engine suppliers, most notably the U.S

Monaghan, Matthew

Trains: Theory and Applications of Ground Vehicle Aerodynamics

1184807/18/2014

This video summarizes Chapter 8 of the book, "Theory and Applications of Aerodynamics for Ground Vehicles", by Dr. T. Yomi Obidi, published by SAE International. Concepts covered include train classification by function and speed, drag effect on design, and lateral force

Theory and Applications of Aerodynamics for Ground Vehicles

R-39203/20/2014

This book provides an introduction to ground vehicle aerodynamics and methodically guides the reader through the various aspects of the subject. Those needing specific information or a refresher can easily jump to the material of interest. There is a particular emphasis on various vehicle types (passenger cars, trucks, trains, motorcycles, race cars, etc.). However, the book is focused on cars and trucks, which are the most common vehicles in the speed range in which the study of ground vehicle aerodynamics is beneficial. Readers will gain a fundamental understanding of the topic, which will help them design vehicles that have improved aerodynamics; this will lead to better fuel efficiency, improved performance, and increased passenger comfort. The author’s basic approach to the presentation of the material is complemented with review questions, application questions, exercises, and suggested projects at the end of most of the chapters, which helps the reader apply the information

Obidi, T. Yomi

Characterisation of the Brake Pads Used in High-Speed Trains

2013-01-2028

09/30/2013

It is essential to characterize the frictional properties of brake pads used in high-speed trains during the processes of development and manufacturing of the pads. This paper presents the test results of new developed composite and powder metallurgical brake pads at different sliding speeds and contact pressures with specially designed test rig. Test results show that the coefficient of friction was increased with the increasing of sliding speed up to 120km/h, but over 120km/h it was decreased with the increasing of sliding speed for the composite brake pads. For the powder metallurgical brake pads, sliding speeds had no significant effect on the friction coefficients of the brake pads. Contact pressure had significant effect on the friction coefficient of brake pads for both materials. Water on the braking contact surfaces had significant effect on the friction coefficient of powder metallurgical brake pads. Temperature had significant effect on the friction coefficient of the powder

Wang, Shuwen, Zhang, Jing-Ming, Yang, Zhenning, Chen, Kang