scholarly journals Numerical Study of Longitudinal Inter-Distance and Operational Characteristics for High-Speed Capsular Train Systems

Vehicles ◽  
2022 ◽  
Vol 4 (1) ◽  
pp. 30-41
Author(s):  
Bruce W. Jo
Keyword(s):  
Error Rate ◽  
High Speed ◽  
Position Control ◽  
Numerical Study ◽  
Design Parameters ◽  
Maximum Speed ◽  
Integer Number ◽  
Vehicle Speed ◽  
Start Time ◽  
Distance Control

High-speed capsular vehicles are firstly suggested as an idea by Elon Musk of Tesla Company. Unlike conventional high-speed trains, capsular vehicles are individual vessels carrying passengers and freight with the expected maximum speed of near 1200 [km/h] in a near-vacuum tunnel. More individual vehicle speed, dispatch, and position control in the operational aspect are expected over connected trains. This numerical study and investigation evaluate and analyze inter-distance control and their characteristics for high-speed capsular vehicles and their operational aspects. Among many aspects of operation, the inter-distance of multiple vehicles is critical toward passenger/freight flow rate and infrastructural investment. In this paper, the system’s equation, equation of the motion, and various characteristics of the system are introduced, and in particular control design parameters for inter-distance control and actuation are numerically shown. As a conclusion, (1) Inter-distance between vehicles is a function of error rate and second car start time, the magnitude range is determined by second car start time, (2) Inter-distance fluctuation rate is a function of error rate and second car start time, however; it can be minimized by choosing the correct second car start time, and (3) If the second car start time is chosen an integer number of push-down cycle time at specific velocity error rate, the inter-distance fluctuation can be zero.

scholarly journals A Study on the Analytic Power Estimation of the Electromagnetic Resonant Energy Harvester for the High-Speed Train

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 403 ◽  
Author(s):  
Jaehoon Kim
Keyword(s):  
Energy Harvesting ◽  
High Speed ◽  
Energy Harvester ◽  
Vertical Direction ◽  
Design Parameters ◽  
Maximum Speed ◽  
Power Sources ◽  
Resonant Energy ◽  
High Speed Trains ◽  
Analytic Estimation

This study is intended to identify the applicability of energy harvesting technologies that are regarded as new electrical power sources for the sensors on high-speed trains. The analytic estimation research is conducted on the amount of electric energy harvested from the high-speed trains, operating at a maximum speed of over 400km/h to verify the applicability of the energy harvesting technology converting the vibration energy of axle and bogie into electric power. Based on the data of the vibration acceleration on the axles and bogies, which were measured by using a 500 Hz analog filter, an analytic estimation on the amount of power harvested by an electromagnetic resonant harvester is conducted through the analysis of the main frequency. The power of the electromagnetic resonant harvester is based on a theoretical model of the mass-spring-damper system, and the harvested power from the axles and bogies in the vertical direction is analytically estimated in this study. The analytic calculations typically give the target value for the final performance of the electromagnetic resonant energy harvester. The targets of the analytic estimations are given to provide the basis for the detailed design and to give a basis for defining the basic design parameters of the electromagnetic resonant energy harvester.

Study on Seismic Isolation of High-Speed Railway Bridge Fabricated Lead Rubber Bearings

2011 ◽  
Vol 80-81 ◽  
pp. 409-413 ◽  
Author(s):  
Huan Tang ◽  
Hui Wang ◽  
Biao Zhou ◽  
Ling Kun Chen
Keyword(s):  
High Speed ◽  
Seismic Isolation ◽  
Computational Method ◽  
Bridge Engineering ◽  
Design Parameters ◽  
Vehicle Speed ◽  
Widespread Application ◽  
Bridge Model ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

Lead rubber bearings (LRB) is a new type of earthquake-resistance rubber bearings, formed by inserting lead-core into ordinary laminated rubber bearings, vertical supporting, horizontal displacement and hysteretic damping are hung in single unit together. Because lead-core can dissipate seismic energy and increase stiffness under load simultaneously, most of the requirements of the Seismic isolation system can be satisfied , the material-device has been found widespread application prospect in bridge Engineering. Equivalent linear model of hysteretic characteristics, computational method and the varying range of design parameters of LRB are presented. A full-bridge model of multi-span simple supported bridge with LRB is established in which box beam、LRB and piers are taken into account as a whole. By changing the property of earthquake excitation, ground motion intensity, vehicle speed and so on, the response of Bridge vibration system are analyzed, response law and characteristics of Bridge with LRB under different excitations are investigated systematically, compared with bridge with common bearings.

scholarly journals Numerical Study on Track–Bridge Interaction of Integral Railway Rigid-Frame Bridge

2021 ◽  
Vol 11 (3) ◽  
pp. 922
Author(s):  
Wenshuo Liu ◽  
Hao Lai ◽  
Gonglian Dai ◽  
Shiwei Rao ◽  
Dezhi Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Threshold Value ◽  
Design Parameters ◽  
Bridge Structure ◽  
Analysis Model ◽  
High Speed Railway ◽  
Rigid Frame ◽  
Track Bridge ◽  
Rigid Frame Bridge

Track–bridge interaction (TBI) is an increasingly essential consideration for the design and operation of railway bridges, especially for the innovative bridge structure systems that constantly spring up over the years. This paper focuses on the characteristics of additional forces in continuous welded rails (CWRs) on the 3 × 70 m integral rigid-frame bridge of the Fuzhou–Xiamen High-Speed Railway, which is a novel high-speed railway (HSR) bridge structure system in China. The differential equations of rail stress and displacement are first investigated and an integrative analysis model comprising of rail, track, bridge and piers is then established. Secondly, the characteristics of representative additional forces are illustrated and the influences of different design parameters are discussed in detail. Furthermore, suitable rail fasteners, optimal layout schemes of adjacent bridges and reasonable stiffness of piers are also studied. The results indicate that the additional expansion force accounts for the largest proportion of additional forces in integral rigid-frame bridges and that resistance reduction obviously weakens the various additional forces caused by the TBI effect, while the broken gap of the rail increases greatly. Small resistance fasteners are recommended to be applied onto this new type of HSR line as these provide reductions in additional stresses of CWRs compared to WJ-8 fasteners. The additional rail stresses after adopting an adjacent span scheme of 4 × 32 m simply supported beams are less than the corresponding stresses in other schemes. The results also show that there is a strong correlation between the minimum threshold value of the pier stiffness and the longitudinal resistance of HSR lines for the integral rigid-frame bridge. This work could serve as a valuable reference for detailed design and safety evaluation of integral rigid-frame bridges.

TERRAIN ROUGHNESS ASSESSMENT FOR HIGH SPEED UGV NAVIGATION IN UNKNOWN HETEROGENEOUS TERRAINS

2010 ◽  
Vol 07 (02) ◽  
pp. 165-176 ◽  
Author(s):  
AHMED EL-KABBANY ◽  
A. RAMIREZ-SERRANO
Keyword(s):  
High Speed ◽  
Life Time ◽  
Closed Form Expression ◽  
Maintenance Cost ◽  
Maximum Speed ◽  
Navigation Systems ◽  
Vehicle Speed ◽  
Range Image ◽  
Transmitted Force ◽  
Terrain Roughness

This paper addresses the problem of determining the maximum allowable speed (V) of a vehicle traversing unknown off-road terrains. The calculated maximum speed achieves the fastest navigation without exceeding an allowable range of transmitted force (Fall) to the vehicle's frame. The proposed system enables the vehicle to transit between different terrains safely. The system's input are: (i) a 3D range image of the terrain and (ii) the vehicle's dimensions and characteristics (e.g., suspension parameters). First the terrain roughness is assessed; then the corresponding maximum allowable speed is calculated. In this paper a novel Roughness Index (RI) is used to represent the terrain roughness. This index is calculated based on the standard deviation of the terrain points' elevations (3D range image). A closed form expression of the maximum allowable vehicle speed is developed (as function of the vehicle's properties, Fall, RI, and probability of not exceeding Fall). The proposed system can be used as a driver assistant system to enhance the vehicle performance, increase its life time, and reduce the maintenance cost. In addition, it is a key module in Unmanned Ground Vehicles (UGVs) navigation systems; as it provides the navigation system with necessary information for path and speed planning.

scholarly journals ANALYSIS OF SPEED AND SOCIAL-PSYCHOLOGY FACTORS OF SPEEDING BEHAVIOUR ON DRIVERS IN DKI JAKARTA

2019 ◽  
Vol 2 (3) ◽  
pp. 133
Author(s):  
Andyka Kusuma ◽  
Dewi Maulina ◽  
Almatrisa Mustika Hutami
Keyword(s):  
Social Psychology ◽  
Reaction Time ◽  
High Speed ◽  
Maximum Speed ◽  
Speed Limit ◽  
Vehicle Speed ◽  
Common Cause

Increased vehicle speed will affect the increase in reaction time and distance to stop and the increased possibility of errors that can be done by the driver. The most common cause of accidents faced by many countries is a high speed and exceeding permitted limits because they contribute to the problem of the number and number of fatalities of accident victims. Setting the maximum speed limit can reduce the risk of accidents. The higher the speed, the greater the stop distance needed, and the risk of accidents increases. Kecepatan kendaraan yang meningkat akan berpengaruh terhadap peningkatan waktu reaksi dan jarak untuk berhenti serta meningkatnya kemungkinan kesalahan yang dapat dilakukan oleh pengemudi. Faktor penyebab kecelakaan yang paling sering dihadapi oleh banyak negara adalah kecepatan tinggi dan melebihi batas yang diijinkan karena ikut berkontribusi pada permasalahan jumlah dan kefatalan korban kecelakaan. Mengatur batas kecepatan maksimum dapat menurunkan resiko kecelakaan. Semakin tinggi kecepatan, maka semakin besar jarak berhenti yang dibutuhkan dan resiko kecelakaan semakin meningkat.

Coupling Impacts of Spray and Rainfall on Road Visibility and Vehicle Speeds: A Simulation-based Analysis

2021 ◽  
Author(s):  
Shuyi Wang ◽  
Tianheng Chen ◽  
Bin Yu ◽  
Yue Sun ◽  
Xiaochun Qin
Keyword(s):  
High Speed ◽  
Traffic Accidents ◽  
Water Film ◽  
Design Parameters ◽  
Vehicle Speed ◽  
Highway Design ◽  
The Road ◽  
Sight Distance ◽  
Rain Medium ◽  
Stopping Sight Distance

Impaired visibility resulting from rainfall contributes greatly to the occurrence of traffic accidents. This study presents a numerical simulation approach to analyze the extent to which the coupling of spray and raindrops reduces visibility and thus proposes safe speeds against inadequate visibility. The spray-raindrop coupling particles were modeled by considering the real highway design parameters and rainfall conditions. The road visibility was estimated through simulating the multiple scattering process of taillights in the spray-rain medium, and the maximum safe speed against inadequate visibility was then derived by comparing the visibility with the required stopping sight distance. Results show that: 1) either a high speed of the front truck or a thick water-film results in a significant reduction in road visibility and the maximum safe speed of the ego vehicle, 2) front vehicle speed plays a more important role in visibility reduction than the water-film thickness does.

Aerodynamic and aeroacoustic performance investigations on modified H-rotor Darrieus wind turbine

2021 ◽  
pp. 0309524X2110039
Author(s):  
Amgad Dessoky ◽  
Thorsten Lutz ◽  
Ewald Krämer
Keyword(s):  
Wind Turbine ◽  
High Speed ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
3D Models ◽  
Power Coefficient ◽  
Design Parameters ◽  
Second Phase ◽  
Vertical Axis Wind Turbine ◽  
Guide Vanes

The present paper investigates the aerodynamic and aeroacoustic characteristics of the H-rotor Darrieus vertical axis wind turbine (VAWT) combined with very promising energy conversion and steering technology; a fixed guide-vanes. The main scope of the current work is to enhance the aerodynamic performance and assess the noise production accomplished with such enhancement. The studies are carried out in two phases; the first phase is a parametric 2D CFD simulation employing the unsteady Reynolds-averaged Navier-Stokes (URANS) approach to optimize the design parameters of the guide-vanes. The second phase is a 3D CFD simulation of the full turbine using a higher-order numerical scheme and a hybrid RANS/LES (DDES) method. The guide-vanes show a superior power augmentation, about 42% increase in the power coefficient at λ = 2.75, with a slightly noisy operation and completely change the signal directivity. A remarkable difference in power coefficient is observed between 2D and 3D models at the high-speed ratios stems from the 3D effect. As a result, a 3D simulation of the capped Darrieus turbine is carried out, and then a noise assessment of such configuration is assessed. The results show a 20% increase in power coefficient by using the cap, without significant change in the noise signal.

scholarly journals CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

2021 ◽  
Vol 11 (9) ◽  
pp. 3934
Author(s):  
Federico Lluesma-Rodríguez ◽  
Temoatzin González ◽  
Sergio Hoyas
Keyword(s):  
Shock Waves ◽  
Power Consumption ◽  
High Speed ◽  
Cfd Simulation ◽  
Aerodynamic Drag ◽  
Flow Behavior ◽  
Critical Conditions ◽  
Vehicle Speed ◽  
Blockage Ratio ◽  
The Cost

One of the most restrictive conditions in ground transportation at high speeds is aerodynamic drag. This is even more problematic when running inside a tunnel, where compressible phenomena such as wave propagation, shock waves, or flow blocking can happen. Considering Evacuated-Tube Trains (ETTs) or hyperloops, these effects appear during the whole route, as they always operate in a closed environment. Then, one of the concerns is the size of the tunnel, as it directly affects the cost of the infrastructure. When the tube size decreases with a constant section of the vehicle, the power consumption increases exponentially, as the Kantrowitz limit is surpassed. This can be mitigated when adding a compressor to the vehicle as a means of propulsion. The turbomachinery increases the pressure of part of the air faced by the vehicle, thus delaying the critical conditions on surrounding flow. With tunnels using a blockage ratio of 0.5 or higher, the reported reduction in the power consumption is 70%. Additionally, the induced pressure in front of the capsule became a negligible effect. The analysis of the flow shows that the compressor can remove the shock waves downstream and thus allows operation above the Kantrowitz limit. Actually, for a vehicle speed of 700 km/h, the case without a compressor reaches critical conditions at a blockage ratio of 0.18, which is a tunnel even smaller than those used for High-Speed Rails (0.23). When aerodynamic propulsion is used, sonic Mach numbers are reached above a blockage ratio of 0.5. A direct effect is that cases with turbomachinery can operate in tunnels with blockage ratios even 2.8 times higher than the non-compressor cases, enabling a considerable reduction in the size of the tunnel without affecting the performance. This work, after conducting bibliographic research, presents the geometry, mesh, and setup. Later, results for the flow without compressor are shown. Finally, it is discussed how the addition of the compressor improves the flow behavior and power consumption of the case.

The Engagement of Hybrid Ultra High Space Division Multiplexing with Maximum Time Division Multiplexing Techniques for High-Speed Single-Mode Fiber Cable Systems

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
P. G. Kuppusamy ◽  
Ahmed Nabih Zaki Rashed ◽  
P. Jayarajan ◽  
M. R. Thiyagupriyadharsan ◽  
...  
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Design Parameters ◽  
Control Parameters ◽  
Data Rates ◽  
Fiber Optic Communication ◽  
High Space ◽  
Optic Communication

AbstractHigh-speed single-mode fiber-optic communication systems have been presented based on various hybrid multiplexing schemes. Refractive index step and silica-doped germanium percentage parameters are also preserved during their technological boundaries of attention. It is noticed that the connect design parameters suffer more nonlinearity with the number of connects. Two different propagation techniques have been used to investigate the transmitted data rates as a criterion to enhance system performance. The first technique is soliton propagation, where the control parameters lead to equilibrium between the pulse spreading due to dispersion and the pulse shrinking because of nonlinearity. The second technique is the MTDM technique where the parameters are adjusted to lead to minimum dispersion. Two cases are investigated: no dispersion cancellation and dispersion cancellation. The investigations are conducted over an enormous range of the set of control parameters. Thermal effects are considered through three basic quantities, namely the transmission data rates, the dispersion characteristics, and the spectral losses.

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