Dynamic Performance Simulation of Overhead Contact System for over 350km/h High-Speed Rail

2013 ◽  
Vol 706-708 ◽  
pp. 1305-1309 ◽  
Author(s):  
Jie Ruan ◽  
An Li ◽  
Fu Wu Yan ◽  
Hong Mei Li
Keyword(s):  
Wave Propagation ◽  
High Speed ◽  
Dynamic Performance ◽  
Propagation Speed ◽  
Contact System ◽  
Running Speed ◽  
High Speed Rail ◽  
Rail Network ◽  
Infinite Element Method ◽  
Wave Propagation Speed

With full development of 350km/h high-speed rail network in China, further research in the key technology of 380km/h or higher super-speed rail system has become crucial. Applying the simulation of pantograph-catenary interaction based on infinite element method, this paper simulated the dynamic performance of pantograph-catenary system for high-tension overhead contact system at over 350km/h. The research findings showed that wave propagation speed can still serve as a brief computing method for the running speed within the range of 350-400km/h. When the running speed reaches 80% of the wave propagation speed or higher, the current-carrying quality of double-pantograph-catenaries system might not satisfy the standard of EN 50367 all the time.

scholarly journals Numerical Investigation of Aerodynamic Drag and Pressure Waves in Hyperloop Systems

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1973
Author(s):  
Thi Thanh Giang Le ◽  
Kyeong Sik Jang ◽  
Kwan-Sup Lee ◽  
Jaiyoung Ryu
Keyword(s):  
Wave Propagation ◽  
Drag Coefficient ◽  
Speed Of Sound ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Propagation Speed ◽  
Pressure Waves ◽  
Wave Propagation Speed ◽  
Pod Length ◽  
Very High

Hyperloop is a new, alternative, very high-speed mode of transport wherein Hyperloop pods (or capsules) transport cargo and passengers at very high speeds in a near-vacuum tube. Such high-speed operations, however, cause a large aerodynamic drag. This study investigates the effects of pod speed, blockage ratio (BR), tube pressure, and pod length on the drag and drag coefficient of a Hyperloop. To study the compressibility of air when the pod is operating in a tube, the effect of pressure waves in terms of propagation speed and magnitude are investigated based on normal shockwave theories. To represent the pod motion and propagation of pressure waves, unsteady simulation using the moving-mesh method was applied under the sheer stress transport k–ω turbulence model. Numerical simulations were performed for different pod speeds from 100 to 350 m/s. The results indicate that the drag coefficient increases with increase in BR, pod speed, and pod length. In the Hyperloop system, the compression wave propagation speed is much higher than the speed of sound and the expansion wave propagation speed that experiences values around the speed of sound.

Influence of the applied pressure of the transducer on the propagation speed of the ultrasonic wave in wood

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Edgar V.M. Carrasco ◽  
Rejane C. Alves ◽  
Mônica A. Smits ◽  
Vinnicius D. Pizzol ◽  
Ana Lucia C. Oliveira ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Applied Pressure ◽  
Pressure Gauge ◽  
Eucalyptus Grandis ◽  
Propagation Speed ◽  
Ultrasonic Waves ◽  
Ultrasonic Speed ◽  
Wave Propagation Speed ◽  
Propagation Technique ◽  
Non Destructive

Abstract The non-destructive wave propagation technique is used to estimate the wood’s modulus of elasticity. The propagation speed of ultrasonic waves is influenced by some factors, among them: the type of transducer used in the test, the form of coupling and the sensitivity of the transducers. The objective of the study was to evaluate the influence of the contact pressure of the transducers on the ultrasonic speed. Ninety-eight tests were carried out on specimens of the species Eucalyptus grandis, with dimensions of 120 × 120 × 50 mm. The calibration of the pressure exerted by the transducer was controlled by a pressure gauge using a previously calibrated load cell. The robust statistical analysis allowed to validate the experimental results and to obtain consistent conclusions. The results showed that the wave propagation speed is not influenced by the pressure exerted by the transducer.

scholarly journals К теории рассеяния Мандельштама-Бриллюэна в плазменном слое

2020 ◽  
Vol 128 (1) ◽  
pp. 98
Author(s):  
С.А. Двинин ◽  
Д.К. Солихов ◽  
Ш.С. Нурулхаков
Keyword(s):  
Wave Propagation ◽  
Pump Wave ◽  
Plasma Layer ◽  
Brillouin Scattering ◽  
Propagation Speed ◽  
Local Source ◽  
Arbitrary Angle ◽  
Perturbation Amplitude ◽  
Wave Propagation Speed ◽  
Over Time

The evolution of a perturbation from a local source for Mandel'shtam-Brillouin scattering in a plasma layer with unlimited length is calculated. Perturbation over time in this case can either leave the scattering region through one of the two boundaries, or propagate along the layer at a speed below sound wave propagation speed, with an exponential growth, or a fall in perturbation amplitude. In the particular case of strictly backward scattering (the scattering angle is π), this propagation velocity is zero. The paper calculates the threshold instability fields and the instability increments, taking into account both convective losses and collisional attenuation of waves. It is shown that the instability threshold for scattering at an arbitrary angle can be lower than for strictly backwards scattering and when the threshold is exceeded by the intensity of the pump wave; the scattering increment at an angle can also be higher than the increment for backscattering. When the threshold is greatly exceeded, the convective losses can be neglected, and the largest increment is observed for backward scattering.

scholarly journals Infrastructure costs and benefits of European high-speed rail

2021 ◽  
Vol 1 (2) ◽  
pp. 47-53
Author(s):  
Nedžad Branković ◽  
Aida Kalem
Keyword(s):  
High Speed ◽  
New Technologies ◽  
Operational Parameters ◽  
Negative Effects ◽  
Railway Network ◽  
High Speed Rail ◽  
Rail Network ◽  
High Speed Trains ◽  
Conventional Rail ◽  
Ecologically Sustainable

The development of new technologies has significantly influenced railways modernization and has caused the appearance of high-speed rail which represent a safe, comfortable and ecologically sustainable way of transportation. The high-speed rail present a big step in a relation to conventional railways, where the biggest difference is speed which even entails a change of other organizational and operational parameters, better utilization of trains, higher performance of manpower and better service to users.  That is visible in many cities around the world where high-speed trains are used by billions of users. In the EU there is no unique high-speed railway network, besides that in many EU member countries various operational models are applied. The future of the high-speed railways market depends on political, economical and technical factors and challenges as high infrastructure costs, various rates of return on investment and the negative effects of economic crises. The main objective of the paper is to analyze infrastucture costs of high-speed rail in Europe and benefits such us  time savings, higher reliability, comfort, safety, reducing pollution and the release of capacity in the conventional rail network, roads and airport infrastructure.

Analytical and Optimization Study of Propagation and Reduction of Wave in Granular Sand by DEM Method

2021 ◽  
Author(s):  
Amin Moslemi Petrudi ◽  
Masoud Rahmani
Keyword(s):  
Wave Propagation ◽  
Particle Density ◽  
Propagation Speed ◽  
Granular Soils ◽  
Discrete Elements ◽  
Factors Affecting ◽  
Interparticle Force ◽  
Optimization Study ◽  
Solution Methods ◽  
Wave Propagation Speed

In this research, the discrete element method has been used to analyze wave propagation and to investigate the factors affecting wave reduction in granular soils. The method of discrete elements is important because of the possibility of preparing completely similar specimens and examining the effect of changes in a certain parameter on the Behavior of the specimens. This method also provides an understanding of the changes that have occurred at the micro-scale of granular materials that are not achievable with other laboratory and numerical methods. To model the specimens, a set of disks with specific granulation has been used for two-dimensional studies. PFC 2D software has been used to perform simulations and related analyzes such as interparticle force. The DEM code in MATLAB is used to check the wave depreciation. In this research, the optimization process was performed using experimental data and the Taguchi method using the DEM method. The results of this study show that there is a direct relationship between the number of particle set contacts and the wave propagation speed. Also, material properties such as particle density are the most important parameters affecting wave velocity. The results of the method (DEM) are done with PFC 2D software and a comparison between the results of this method with the solution methods used by other researchers is shown to be a good match.

Axial force measurement for U-bolt using wave propagation speed monitoring

2016 ◽  
Vol 140 (4) ◽  
pp. 3002-3002
Author(s):  
Gyungmin Toh ◽  
Dongki Min ◽  
Jaehong Lee ◽  
Junhong Park
Keyword(s):  
Wave Propagation ◽  
Axial Force ◽  
Force Measurement ◽  
Propagation Speed ◽  
Wave Propagation Speed

scholarly journals Schedule-Based Passenger Assignment for High-Speed Rail Networks considering the Ticket-Booking Process

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Huanyin Su ◽  
Feng Shi ◽  
Guangming Xu ◽  
Jin Qin ◽  
Xinghua Shan
Keyword(s):  
High Speed ◽  
Continuous Process ◽  
Operating Efficiency ◽  
High Speed Rail ◽  
Rail Network ◽  
Assignment Method ◽  
Rail Systems ◽  
Improvement Measures ◽  
Passenger Assignment ◽  
Partition Interval

This paper proposes a schedule-based passenger assignment method for high-speed rail networks considering the ticket-booking process. Passengers book tickets to reserve seats during the presale period in high-speed rail systems and passengers on trains are determined during the ticket-booking process. The ticket-booking process is modeled as a continuous and deterministic predecision process. A solution algorithm is designed using the discretization of the continuous process by partitioning the ticket-booking time and the optimal paths remain constant in any partition interval. Finally, an application to the Chinese high-speed rail network is presented. A comparison of the numerical results with the reality is conducted to validate the efficiency and precision of the method and algorithm. Based on the results, the operating efficiency of the current train schedule is evaluated and some specific improvement measures are proposed.

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