Maximum Design Speed Research Articles

Assessment of Design Consistency for Two-Lane Rural Highways with Low Tortuosity Alignment

One technique employed to enhance road safety involves assessing the alignment’s consistency. A prevalent measure of consistency is evaluating speed variations along the alignment. A key consideration in this assessment is determining the speed upon which the road alignment should be based. This research reveals that on two-lane rural highways with low tortuosity alignments, operating speeds on horizontal curves and tangents consistently exceeded not only the design speeds but also the maximum permissible design speed for the road category. Consequently, using the design speed to assess consistency on these roads is deemed impractical, and utilizing operating speed poses challenges due to speeds exceeding the maximum permissible limit. The objectives of this paper are twofold: to explore the relationship between design consistency and safety levels on two-lane rural highways with low tortuosity alignments (which have been insufficiently covered in research) and to propose speed-control measures to limit the maximum operating speed to the maximum permissible speed. The study findings suggest that on roads with a low tortuosity alignment, operating speeds depend much more on the general characteristics of the alignment (evaluated in the operating speed models through the desired speed). Further, assessing speed consistency is feasible only with a rigorous control of the maximum operating speed (desired speed). Additionally, a specific type of speed control is recommended, achieved by limiting the curvature change rate (CCR) of the road section based on the desired speed (environmental speed), whose evaluation becomes a crucial factor.

Numerical analysis of the influence of granular trench reinforcement of soft clay subgrade on the undrained dynamic response of a railway track

Soft subgrade poses significant challenges to the designer of railway tracks due to its high compressibility and low shear wave velocity. The low shear wave velocity might affect the maximum design speed of the train. The stabilization of this soft soil improves its performance and reduces the expected settlement. However, little attention has been paid to understanding the feasibility of different stabilization techniques, as there are very few studies on this topic. Thus, this research study aims to determine the impact of granular trench reinforcement of soft subgrade on the dynamic response of a railway track subjected to a moving train load. Three-dimensional finite element analysis has been used in this research. The effect of the train speed and the depth of the granular trench has been carefully evaluated. It has been found that the critical velocity (which is the velocity that corresponds to the highest settlement) is not affected by the granular trench reinforcement. In addition, it has been noted that the granular trench reinforcement reduces the maximum settlement of the railway track under the moving loads, with a percentage reduction ranging between 1% and 24%. Furthermore, the granular trench reinforcement did not affect the acceleration induced in nearby areas due to the train’s vibration. The results of this research provide useful insight into the feasibility of the granular trench and help design engineers compare different solutions for the problems of soft subgrade soil.

Design, Build, and Evaluation of an AC Loss Measurement Rig for High-Speed Superconducting Bearings

Friction and heat generated in conventional bearings impose a limit on maximum design speed in electrical machines. Superconducting bearings offer the potential for low loss, simplified, and passively stable bearings that can overcome the speed limit and operate at high loads. Although such bearings are contactless and seem to be loss free, AC loss mainly caused by magnetic field inhomogeneity gradually slows down the rotating body. This loss, whose mechanism has not been fully explored, is measured through spin-down tests where the rotational speed of the spinning rotor is measured as a function of time. However, there are some challenges in performing a reliable spin-down test. In this paper, we discuss these challenges as well as the engineering of an experimental test rig that enables us to spin-up, release, and recapture the levitated permanent magnet. We also discuss the specifications of the driving mechanism including the self-aligning coupling, which accommodates permanent magnets of different sizes. Initial test results at 6600 rpm are discussed and further technical improvements to the test rig suggested. This rig will be used as a key tool to explore the AC loss mechanism and inform the design of bearings for high-speed superconducting machines.

Покращення тягового-швидкісних властивостей вдосконаленням методів вибору параметрів моторно-трансмісійної установки автомобіля

Aerodynamic characteristics have a major impact on the energy efficiency and traction and speed properties of the vehicle. In this article, based on previous studies of the aerodynamic characteristics of various car models, we propose an improved method for selecting engine and transmission parameters at the design stage. The aim of the study is to improve the dynamic properties of the car by improving the method of selecting the main parameters of the engine-transmission unit by refining the calculation of aerodynamic drag. To achieve it, the following tasks must be solved: to specify the method of selecting the maximum effective engine power; to specify a technique of definition of the maximum constructive speed of the car; to develop a technique for selecting gear ratios. The aerodynamic resistance to the movement of the vehicle is determined by the frontal coefficient of the specified resistance, the density of the air, the area of the frontal resistance and the speed of the vehicle. It is known from classical works on the aerodynamics of a car that in the range of vehicle speeds from 20 m / s to 80 m / s, taking the law of squares when assessing the force of air resistance, it is necessary to change the coefficient of frontal aerodynamic drag depending on the speed of the car. However, when carrying out calculations, this coefficient is taken constant, which leads to obtaining large values of the air resistance force at high speeds and lower at low speeds. There are two possible ways to improve the dynamic properties and energy efficiency of the car during its modernization (increasing the maximum design speed of the car by reducing the gear ratio in higher gear; reducing the maximum efficiency of the engine while maintaining the previous gear ratio in higher gear). As a result of the study, the method of selection (maximum effective engine power; maximum design speed of the car; gear ratios) at the design stage of the parameters of the motor-transmission unit of the car has been improved.

Developing Railway Link in Central Region of Romania

An intersection of European Railway Corridors is present in our country by geographical meanings, conducting to a need of developing infrastructure and connecting it to the European Corridors. The railway link between the Romanian Regions is developing and has just a few sections that need to be made in order to have the entire IVth Pan European Railway Corridor from Romania rehabilitated. The Central Developing Region from Romania contains the railway section between Brasov and Sighisoara cities that is rehabilitated for the maxim design speed for passenger trains of 160 km/h and 120km/h for freight trains. The maximum design speed imposes new curves with bigger radius resulting in new routes along the section. The actual and proposed route of double track railway section between Brasov and Sighisoara is analysed and the rehabilitation works along with it. The tunnels cross section and possible difficulties in realising and execution of them are presented and analysed. Conclusions regarding the proposed art works and future problems that can be solved in this stage – preparation stage that can assure better and safe construction and exploitation of the railway are made in final.

Horizontal Alignment Security Design Theory and Application of Superhighways

In China, the maximum design speed of highways is 120 km/h, which first appeared in the Highway Engineering Technical Standard (Trial) in 1951. However, vehicle performance, road design, and construction technology have been greatly improved over the past 68 years. To adapt to the development demands of highway design speeds above 120 km/h in the future, it is urgent to study superhighway alignment design theory. Therefore, the horizontal alignment security design theory of superhighways was developed in this paper. First, the definition, classification, and construction mode of a superhighway and suitable vehicles of different grades are presented. Then, the lengths of straight lines were limited to reduce driving fatigue. Next, the minimum radii of circular curves were calculated based on driver characteristics and stress analysis of operating vehicles. Finally, the minimum lengths of transition curves were calculated based on the centrifugal acceleration of the operating vehicles, the travel time, and the passenger visual characteristics. The calculation and analysis results show that the superhighway linear features conform to the vehicle operating characteristics, and can ensure the safety of driving.

Road safety risk factors for non-motorised vehicle users in a Chinese city: an observational study

ObjectiveThe objective of this study is to describe and analyse the prevalence of speeding, helmet use and red-light running among riders of non-motorised vehicles (NMVs) in Shanghai, China, with a...

Legislative Framework up to the Year 2017. Vehicle Type-Approval.

Considering that motor vehicles must comply with mandatory and mandatory uniform characteristics between the Member States of the European Union in order to eliminate or at least reduce the obstacles to the establishment and functioning of the common market , characteristics that starting from the year 1970 must be adopted both as a complement and in replacement of the current legislation of the member countries; whereas a check of compliance with the technical requirements has traditionally been carried out by the Member States before the vehicles to which they apply are applied and that this control covers the various types of vehicles, the EEC directive number 156 of 1970 defined the first rules of approval that the member Staes EU must adopt to allow the free movement of motor vehicles in safety. Considers vehicles for any motor vehicle designed to travel on the road, with or without a body, having at least four wheels and a maximum design speed exceeding 25 km / h, as well as its trailers, with the exception of vehicles moving on rails , tractors and agricultural machinery. In this publication (2018-19,06) research and studies are carried out in the field of legislation and vehicle type approval techniques with an interest in the evolution of the regulatory framework up to the year 2017. In the appendix the study of some analytical methods used for the construction and design of internal combustion engines with positive ignition (petrol engines) and compression ignition (diesel engines).

A theoretical study of rotatable renewable energy system for stratospheric airship

Renewable energy system is very critical for solving the energy problem of a long endurance stratospheric airship. Output performance of the traditional solar array fixed on the upper surface of the airship remains to be improved to reduce the area and weight of renewable energy system. Inspired by the solar tracking system and kirigami, a rotatable renewable energy system (mainly including solar array) is designed to improve the current status of the energy system. The advantages of the rotatable solar array are studied using a MATLAB computer program based on the theoretical model established in this paper. The improvements in output energy and required area of the solar array were compared between the traditional airship and improved one. Studies had shown that the rotatable renewable energy system made the total weight of energy system decreased by 1000kg when the maximum design speed of the airship was greater than 22m/s. The results demonstrate that the rotatable renewable energy system for the airship can be a good way to improve the output performance of solar array, and the conceptual design and theoretical model suggest a pathway towards solving the energy problem of a stratospheric airship.

Development of Flight Control System and Troubleshooting on Flight Test of a Tilt-Rotor Unmanned Aerial Vehicle

The full results of troubleshooting process related to the flight control system of a tilt-rotor type UAV in the flight tests are described. Flight tests were conducted in helicopter, conversion, and airplane modes. The vehicle was flown using automatic functions, which include speed-hold, altitude-hold, heading-hold, guidance modes, as well as automatic take-off and landing. Many unexpected problems occurred during the envelope expansion tests which were mostly under those automatic functions. The anomalies in helicopter mode include vortex ring state (VRS), long delay in the automatic take-off, and the initial overshoot in the automatic landing. In contrast, the anomalies in conversion mode are untrimmed AOS oscillation and the calibration errors of the air data sensors. The problems of low damping in rotor speed and roll rate responses are found in airplane mode. Once all of the known problems had been solved, the vehicle in airplane mode gradually reached the maximum design speed of 440km/h at the operation altitude of 3km. This paper also presents a comprehensive detailing of the control systems of the Tilt-rotor unmanned air vehicle (UAV).

Influence Resistance at Advancing on Fuel Consumption for Vehicles that use an Internal Source of Energy

In the case of railway traction, an analysis on the influence the running resistance about the fuel consumption for the motors vehicles equipped with an internal source of energy(diesel engine or gas turbine) is necessary and from the perspective of the optimal way of their exploitation. This paper aims to determine the influence they have the aerodynamic phenomena on the running resistance and therefore to the fuel consumption, in case of traction vehicles equipped with diesel motors which are operated by the railway companies in Romania. To achieve the study, we considered the following vehicles: diesel electric locomotives LDE 060 DA of 2100 CP, LDE 060 DD of 4000 CP, LDE 060 EGM of 2100 CP, Carpathia DEM of 2300 CP and railcar Siemens Desiro. The calculation of fuel consumption is achieved in case of a path segment with a length of 1000m. In this sector, the above-mentioned vehicles were analyzed in three distinct situations: when moving with the maximum design speed kept constant; when towing of maximum tonnage when moving a constant speed; and when it is in the process of starting. This article is developed in the programs postdoctoral studies at the University Politehnica of Bucharest.

Calculation on Internal Force Effect of a High-Speed Highway Prestressed Concrete Extra-Dosed Cable-Stayed Bridge

The Extra-dosed cable-stayed bridge is considered as a new popular type of bridge structure in recent 20 years, whose mechanical properties and economic span both lie between continuous beam (or rigid frame ) bridges and cable-stayed bridges. This design is a double-cable-plane (85+150+85) m prestressed concrete Extra-dosed cable-stayed bridge, whose maximum Design speed is 100km/h and its width is 25.50m. The form of the highway is sextuple line which is 10.75m far away,and the cross-sectional slope is 2%. The girder body adopts three cell and single box, the height of beam takes quadratic parabola relation, which is 5m high at the middle support, while at the side support and the midspan is 3m. Vehicle standard load was applied on the bridge. The design uses Midas/Civil to establish the finite element model that is reasonable and simple, analyzing the structure behavior of the girder body under loading, especially the internal forces of bridge structure under dead load, live load and additional force.

Air Gap Control Simulation of Maglev Vehicles with Feedback Control System

The purpose of this paper is to more realistically predict the air gaps of the maglev vehicles under consideration. For doing so, the much more detailed dynamic modeling techniques, considering all the components are presented. In EMS-type maglev, air gap which is clearance between guideway surface and supporting magnet should be maintained within a limited value for preventing physical contact. The levitation control unit consists of electromagnets, gap sensors, choppers, and a controller. Thus, it would be desirable to include all the mechanical and electrical parts in the air gap simulation model. With the proposed model, air gaps are simulated to evaluate whether the mechanical contact would be occurred at maximum design speed.

Study on Internal Force Effect of a High-Speed Rail (40+56+40) m Prestressed Concrete Continuous Beam Bridge

The continuous beam bridge is a kind of bridge type used widely on the project. With the design theory and construction technology, prestressed concrete continuous beam bridge shown strong vitality. This design is a high-speed rail (40+56+40) m prestressed concrete continuous beam bridge design, whose width is 12.2m and its maximum Design speed is 300km/h. The form of the railway is double line which is 4.8m far away, and the cross-sectional slope is 2%.ZK load was applied on the bridge. A three-span P.C continuous Beam structure with variable cross-section is used in this bridge. The girder body adopts single cell and single box, the height of beam takes quadratic parabola relation, which is 5m high at the middle fulcrum, while at the side fulcrum and the mid-span is 2.5m. The design uses Midas/Civil to establish the finite element model that is reasonable and simple, analyzing the structure behavior of the girder body under loading, especially the internal forces of bridge structure under dead load, live load and additional force.

Dynamic Wheel Loads of High-Speed Rail at Speeds Greater than 400 km/h

The high-speed rail (HSR) line in South Korea has been in service since 2004 with a maximum design speed and operating speed of 350 km/h and 300 km/h, respectively. Recently, South Korea developed a high-speed electric multiple unit (HEMU-430X, 430-km/h eXperiment) with a maximum design speed and operating speed of 430 km/h and 400 km/h, respectively; the government was waiting for a trial run on a conventional HSR line. This study tried to predict wheel load fluctuation (WLF), one of the key factors affecting acceleration to speeds over 400 km/h. For WLFs to be understood accurately in the high-speed range greater than 400 km/h, field running tests were performed twice with the KTX-Sancheon trains on the Gyeongbu high-speed line. The trains traveled between Gwangmyeong and Daejeon at maximum running speeds of 302 and 335 km/h, respectively, and WLFs were measured with a telemetry system (radio data transmitter and receiver system) at varying speeds. On the basis of probabilistic data analysis with a Gaussian function, the WLF (σ/Pst) normalized nondimensional parameter at speeds of 400 km/h and 500 km/h was modeled into quadratic functions. The WLFs at speeds of 400 km/h and 500 km/h were predicted to be 0.356 and 0.512, respectively. In addition, impacts from structures that greatly affected WLFs, such as turnouts, transition zones, and loose sleepers, were evaluated quantitatively. Of those, turnouts had the greatest impacts on the WLFs.

ROAD: Interactive Geometric Design Tool for Transportation Education and Training

Traditionally, transportation engineering students have used engineering drawing techniques to manually lay out lines and curves over contour maps for highway geometric design. The design process requires numerous calculations of stopping sight distance, minimum turning radius, and curve alignments to minimize economic and environmental impact and construction costs. Students usually perform iterative computations to manually meet design criteria and environmental constraints. The traditional approach of learning geometric design is cumbersome and time consuming, limiting students from taking a broader perspective on geometric design. A new software tool, Roadway Online Application for Design (ROAD), was developed to enhance the learning experience for transportation engineering students. This tool allows students to design roadway geometry efficiently and modify the design easily within given economic and environmental parameters. The objective is to provide a comprehensive tool that can be accessed easily by students in order to help them better understand geometric design. ROAD can also generate a three-dimensional roadway geometry model at final design to allow students to place themselves in the driver's seat and maneuver through the designed roadway at maximum design speed. DOI: 10.1061/(ASCE)EI.1943-5541 .0000142. © 2013 American Society of Civil Engineers.

3D Animation Applications in Highway Design

Traditionally, highway engineers use pencil and ruler to lay out lines and curves over contour maps for highway geometry design. Numerous calculations of stopping sight distance, minimum turning radius, and curve alignments are required during the design process to ensure safety, to minimize economic and environmental impact, and to reduce construction costs. Engineers usually perform iterative computations manually during the design process to meet design criteria and environmental constraints. The traditional process of highway geometry design is cumbersome and time consuming. The traditional approach limits engineers from taking a broader perspective in the overall highway geometry design process. Current method of three dimensional (3D) has nothing to do with highway design process. CARD/1 was developed to enhance the learning experience for highway engineers. This tool allows engineers to design the highway efficiently and to modify the design easily. A 3D highway geometry model can be generated by the software at final design to allow engineers to place themselves in the driver’s seat and maneuver through the designed highway at maximum design speed. Some key technologies of highway design with 3D-animaion based on CARD/1 was discussed in this paper.

Experimental and numerical investigation on dynamic amplification factors of an urban maglev guideway

The Korean urban maglev project was initiated with the intention of building a commercial line by 2012. An optimized guideway has been proposed and relevant tests are currently being conducted. However, the Dynamic Amplification Factor (DAF) for the maglev guideway has yet to be determined. As the maglev load is distributed rather than concentrated, further examination of dynamic behavior is required. The objective of this study was to identify the DAF of the proposed urban maglev guideway via moving-load analyses. For this purpose, a full-scale guideway girder test and a field test were conducted to identify the modal properties. A finite element model was then developed and verified against test results. Finally, moving load analyses were performed up to the maximum speed. Guideway deflection, longitudinal stresses, and support reactions were measured for various vehicle speeds—DAFs were thus computed. It was found that DAFs for maglev guideways are less than 2.5% at the maximum design speed. This implies that dynamic amplification need not be a severe consideration for the proposed maglev system.

Development of an Online Roadway Geometry Design Software for Transportation Education and Training

Traditionally, students use pencil and ruler to lay out lines and curves over contour maps for roadway geometry design. Numerous calculations of stopping sight distance, minimum turning radius, and curve alignments are required during the roadway design process in order to ensure safety, to minimize economic and environmental impacts, as well as to reduce construction costs. Students usually perform iterative computations manually during the design process in order to meet any given design criteria and environmental constraints. The traditional process of roadway geometry design is often cumbersome and time consuming. The traditional approach limits students from taking a broader perspective of the overall roadway geometry design process. An Internet-based roadway design tool (ROAD: Roadway Online Application for Design) was developed to enhance the learning experience for transportation engineering students. This tool allows students to efficiently design and to easily modify the roadway design with given economic and environmental parameters. A 3D roadway geometry model can be generated by the software at final design to allow students immerse themselves in the driver’s seat and drive through the designed roadway at maximum design speed. This roadway geometry design tool was deployed in a civil engineering undergraduate class in 2006 and 2007 at Department of Civil Engineering, University of Minnesota. Survey results from students indicated the ROAD software enhances their learning experiences in performing roadway geometry design.

Application of Novel Dewatering Element for High Speed Former

The maximum design speed in today's paper machine has been reaching to 2, 000 m/min for achievement the higher productivity demands. At the same time the requirement for higher quality for each paper grade has been increasing from year to year.Mitsubishi Heavy Industries has developed a new technology that combines the best aspect of roll and blade gap forming through extensive fundamental research works.The new technology consists of replacing the initial forming zone with a Groovedfoil blade design. This paper describes the fundamental study and test results of pilot machine trial for dewatering elements.