scholarly journals Influencing Factors on Vehicles Lateral Stability on Tunnel Section in Mountainous Expressway under Strong Wind: A Case of Xi-Han Highway

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Lu Wang ◽  
Xiaoxin Chen ◽  
Hong Chen
Keyword(s):  
Influencing Factors ◽  
High Speed ◽  
Road Traffic ◽  
Theoretical Research ◽  
Driving Safety ◽  
Mountainous Area ◽  
Strong Wind ◽  
Lateral Stability ◽  
Tunnel Section ◽  
Circular Curve

When a car is running at high speed, the canyon wind at the bridge-tunnel junction in the mountainous area brings along the acceleration effect. The aerodynamic lateral force will cause the vehicle sideslip and unsteady steering, which is extremely harmful to driving safety. In this paper, Xi-Han Expressway is taken as the research object to analyze the influencing factors of vehicle’s lateral stability by combining the theoretical research of the finite element method, automobile aerodynamics, and speed limit with field investigation and simulation test. CarSim software is used for simulation to explore the influence of different positions of the circular curve on vehicle lateral stability. The results show that the wind level affects the tunnel exit’s unfavorable section on the circular curve. The larger the wind level, the larger the proportion of the tunnel exit’s unfavorable section on the circular curve. The proportions of tunnel exit’s unfavorable section on the circular curve under 6–9 wind levels are 33.33%, 38.89%, 55.56%, and 66.67%, respectively. In addition, the lateral stability of vehicles under level 6–8 wind scale is the worst when the tunnel exit is located at 5° position on the circular curve. The results indicate the influence of strong wind on the lateral stability of vehicles in mountainous expressway. The research can optimize the design of the highway tunnel group and provide the basic theory and method basis for the quantitative management and scientific management of the road traffic management department.

scholarly journals Theoretical Research on Longitudinal Profile Design of Superhighways

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yongming He ◽  
Yuting Song ◽  
Yulong Pei ◽  
Bin Ran ◽  
Jia Kang
Keyword(s):  
High Speed ◽  
Longitudinal Profile ◽  
Theoretical Research ◽  
Driving Safety ◽  
Design Parameters ◽  
Minimum Length ◽  
Slope Length ◽  
Longitudinal Slope ◽  
Profile Design ◽  
The Impact

To improve driving safety on superhighways, longitudinal profile design parameters of a superhighway are calculated via force analysis while a car is driven on a slope. The calculations consider characteristics of drivers, cars, and roads. According to the vehicle type, design speed, and natural conditions, the maximum longitudinal slope of a superhighway is calculated and compared with those of an ordinary superhighway and high-speed railway. Based on analysis of the vehicle climbing performance, braking performance, and driver visual characteristics, the maximum and minimum slope lengths of a superhighway are calculated. By analyzing the elements of vertical curves, the minimum radius and minimum length of the vertical curves of a superhighway are calculated by considering factors such as mitigating the impact at the slope bottom, driving at night, and driving time along vertical curves. Analysis and calculation results show that when the maximum longitudinal slope is 2.50%, 2.25%, and 2.00%, the minimum slope length is 450 m, 400 m, and 350 m, respectively, and the minimum vertical curve length is 145 m, 130 m, and 115 m, respectively, and the superhighway travel requirements can be satisfied at speeds of 180 km/h, 160 km/h, and 140 km/h, respectively.

Research on the Traffic Safety on the Section of Expressway with Crosswind in Mountainous Area

2014 ◽  
Vol 694 ◽  
pp. 102-108
Author(s):  
Zheng Yi Zhang ◽  
Gao Lu Qian ◽  
Qiang Wang ◽  
Ling Wu
Keyword(s):  
Traffic Safety ◽  
High Speed ◽  
Lateral Force ◽  
Driving Safety ◽  
Horizontal Wind ◽  
Mountainous Area ◽  
Speed Limit ◽  
Mountainous Areas ◽  
Factors Affecting ◽  
Security Issues

When we drive vehicle on expressway in the mountainous areas, there are many factors affecting driving safety. Especially when we drive at a high speed, pneumatic lateral force under the effect of horizontal wind will cause wheels cornering and unsteady steering, which affects the safety of driving. Based on the driving characteristics on the section of expressway with crosswind in mountainous areas, and three security issues that are vehicle roll, cornering and sideslip under the action of crosswind, this paper gives the various speed limit and proposes effective measures to ensure traffic safety, all of which can offer decision-making basis for traffic safety administration of the mountain expressway.

scholarly journals Identification of Sleeper Support Conditions Using Mechanical Model Supported Data-Driven Approach

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3609
Author(s):  
Mykola Sysyn ◽  
Michal Przybylowicz ◽  
Olga Nabochenko ◽  
Lei Kou
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Dynamic Interaction ◽  
Theoretical Research ◽  
Rolling Stock ◽  
Monitoring Methods ◽  
Beam Dynamic ◽  
Track Geometry ◽  
Data Driven Approach ◽  
Support Conditions

The ballasted track superstructure is characterized by a relative quick deterioration of track geometry due to ballast settlements and the accumulation of sleeper voids. The track zones with the sleeper voids differ from the geometrical irregularities with increased dynamic loading, high vibration, and unfavorable ballast-bed and sleeper contact conditions. This causes the accelerated growth of the inhomogeneous settlements, resulting in maintenance-expensive local instabilities that influence transportation reliability and availability. The recent identification and evaluation of the sleeper support conditions using track-side and on-board monitoring methods can help planning prevention activities to avoid or delay the development of local instabilities such as ballast breakdown, white spots, subgrade defects, etc. The paper presents theoretical and experimental studies that are directed at the development of the methods for sleeper support identification. The distinctive features of the dynamic behavior in the void zone compared to the equivalent geometrical irregularity are identified by numeric simulation using a three-beam dynamic model, taking into account superstructure and rolling stock dynamic interaction. The spectral features in time domain in scalograms and scattergrams are analyzed. Additionally, the theoretical research enabled to determine the similarities and differences of the dynamic interaction from the viewpoint of track-side and on-board measurements. The method of experimental investigation is presented by multipoint track-side measurements of rail-dynamic displacements using high-speed video records and digital imaging correlation (DIC) methods. The method is used to collect the statistical information from different-extent voided zones and the corresponding reference zones without voids. The applied machine learning methods enable the exact recent void identification using the wavelet scattering feature extraction from track-side measurements. A case study of the method application for an on-board measurement shows the moderate results of the recent void identification as well as the potential ways of its improvement.

The Analysis and Design of the Dynamic Information Service System Network Architecture of the SOA Based on WAVE Technology

2014 ◽  
Vol 1044-1045 ◽  
pp. 1380-1383
Author(s):  
Guang Li Yin
Keyword(s):  
Network Architecture ◽  
High Speed ◽  
Service System ◽  
Road Traffic ◽  
Rapid Development ◽  
Information Service ◽  
Advanced Technology ◽  
Living Standard ◽  
Vehicle Speed ◽  
Analysis And Design

Safety problem is one of the most attention and concern of driving. This paper in the high-speed on the road cars and car, car and road communications, vehicle real-time status, through the network information service system integration on a platform, on the use of related technologies are analyzed, the design of the software system based on SOA architecture.Keywords: network, GPS module, SOA cross platformI. IntorductionWith the development of science and technology and the improvement of people's living standard, Car popularity rate is high, it's hard to believe, families has two or three car. Whether it is the bus or private car is such rapid development, this will bring a lot of problems in road traffic, such as traffic congestion, traffic accident. These problems affect the normal life and travel, it is necessary to carry out management and provide information service for road use advanced technology. Using mobile phone GPS positioning module can obtain the vehicle speed and the basic information, through processing and optimization of information service system, the analysis of data useful, so as to divert traffic, both for the convenience of the user, but also improve the expressway management ability.

OPTIMISING ROAD LIGHTING TO REDUCE ROAD TRAFFIC CRASHES

2021 ◽  
Author(s):  
C.J. Robbins ◽  
S. Fotios ◽  
J. Uttley ◽  
R. Rowe
Keyword(s):  
High Speed ◽  
Road Traffic ◽  
Cost Benefit ◽  
Light Level ◽  
Traffic Crashes ◽  
Road Traffic Crashes ◽  
Road Lighting ◽  
Road Users ◽  
Ambient Light Level ◽  
Vulnerable Road Users

Pedestrians and motorcyclists are vulnerable road users, being over represented in road traffic collisions (RTCs). One assumed benefit of road lighting is a reduction in RTCs after dark by countering the impairment to the visual detection of hazards that occur after dark. One way to optimise the use of road lighting is to light only those sections of road where light level, and hence visibility, is an important factor. The current study used change in ambient light level on RTCs to investigate those situations where improved vision is likely to have significant impact, and therefore the situations where road lighting is of better cost-benefit effectiveness. For both motorcyclist and pedestrian RTCs there was a significant increase in overall RTC risk in darkness compared to daylight, indicating that there may be an overall benefit of road lighting. While darkness was a particular detriment at junctions for motorcyclists and on high-speed roads for pedestrians, road lighting may not be effective mitigation in either case and therefore alternative ways of increasing conspicuity should be considered.

INVESTIGATION OF THE ABSOLUTENESS OF TIME

2021 ◽  
pp. 51-54
Author(s):  
S. Tiguntsev
Keyword(s):  
High Precision ◽  
Gravitational Potential ◽  
High Speed ◽  
Relativistic Effect ◽  
Theoretical Research ◽  
Clock Frequency ◽  
Positioning Systems ◽  
The Earth ◽  
Flow Of Time ◽  
The Difference

In classical physics, time is considered absolute. It is believed that all processes, regardless of their complexity, do not affect the flow of time The theory of relativity determines that the flow of time for bodies depends both on the speed of movement of bodies and on the magnitude of the gravitational potential. It is believed that time in space orbit passes slower due to the high speed of the spacecraft, and faster due to the lower gravitational potential than on the surface of the Earth. Currently, the dependence of time on the magnitude of the gravitational potential and velocity (relativistic effect) is taken into account in global positioning systems. However, studying the relativistic effect, scientists have made a wrong interpretation of the difference between the clock frequency of an orbiting satellite and the clock frequency on the Earth's surface. All further studies to explain the relativistic effect were carried out according to a similar scenario, that is, only the difference in clock frequencies under conditions of different gravitational potentials was investigated. While conducting theoretical research, I found that the frequency of the signal changes along the way from the satellite to the receiver due to the influence of Earth's gravity. It was found that the readings of two high-precision clocks located at different heights will not differ after any period of time, that is, it is shown that the flow of time does not depend on the gravitational potential. It is proposed to conduct full-scale experiments, during which some high-precision clocks are sent aboard the space station, while others remain in the laboratory on the surface of the earth. It is expected that the readings of the satellite clock will be absolutely identical to the readings of the clock in the Earth laboratory.

Typical Portal Structure for Single Track High Speed Railway Tunnel in Rugged Mountainous Area with High and Abrupt Slope

2014 ◽  
Vol 716-717 ◽  
pp. 342-346
Author(s):  
Xiao Jun Zhou ◽  
Bo Jiang ◽  
Yue Feng Zhou ◽  
Yu Yu
Keyword(s):  
High Speed ◽  
Southwest China ◽  
Earth Pressure ◽  
Mountainous Area ◽  
Single Track ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Railway Line ◽  
Bridge Abutment

On the basis of different landform and multifarious topography in rugged mountainous area in southwest China, typical tunnel portals for single track tunnels in a new high speed railway line have been presented in the paper. The portal comprises headwall, shed tunnel, bridge abutment and its support. Portal with headwall is suitable for tunnel to resist front earth pressure on high and abrupt slope. Shed tunnel is placed in front of headwall so as to prevent rockfall; its outward part is built into a flared one. Meanwhile, the installation of bridge and its abutment are also included in the portal according to landform in the paper.

The Designing and Wear Simulation of the Wheel Used in Super-High Speed Point Grinding

2011 ◽  
Vol 175 ◽  
pp. 177-182
Author(s):  
Ya Dong Gong ◽  
Yue Ming Liu ◽  
Ting Chao Han ◽  
Jun Cheng
Keyword(s):  
High Precision ◽  
High Speed ◽  
Theoretical Research ◽  
Wear Simulation ◽  
Grinding Parameters ◽  
Specific Shape ◽  
Air Hole

The application of the wheel used in super-high speed point (SHSP) grinding is introduced in detail, depicting the applied rang of the wheel, through designing the wheel body and the layer of CBN in the wheel. The designed principle is inferred according to the specific shape, the grinding productivity is analyzed in the course grinding zone and the finished grinding zone, introducing the angle of course grinding zone, which affects the grinding parameters in SHSP grinding, the value of the angle is designed to be suited to the point grinding, and manufacturing the wheel, introducing the changed state of chip flowing grinding used in the new wheel, the micro-surface of the wheel is observed through microscope, whose the ratio of air hole and the layer of CBN are analyzed, simulating the wear trend of the new wheel, the conclusions about super hard abrasives and wearing are drawn at last, the application of SHSP grinding is related to designing and manufacturing of the wheel, which provides the equipment for realizing high precision and productivity processing and offers the referred basis for the theoretical research.

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