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The deviation angle for one-lane roundabouts: A general mathematical formulation and application

Journal of Traffic and Transportation Engineering(English Edition) 2022年第1期9卷 44-58页

作者： Nicola Berloco Pasquale Colonna Paolo Intini Department of Civil EnvironmentalLandBuilding Engineering and ChemistryPolytechnic University of BariBari 70125Italy

Properly designed roundabouts may lead to safety improvements based on both reducing approaching speeds and controlling traffic. Measurements of deflection of vehicle trajectories are commonly used to estimate roundabout speed control. One of these measurements is the deviation angle, which is mentioned in both the Italian and Swiss road standards and, in specific conditions, can be more effective than other methods.This article presents a general mathematical formulation for linking several geometric parameters with the deviation angle in different rural and urban one-lane roundabout configurations, which is currently missing in the literature. For urban roundabouts, refuge islands for pedestrians and cyclists were considered. Based on the proposed formulation, a sensitivity analysis of the influential geometric parameters was conducted. Results suggest that an insufficient deflection of trajectories(deviation angle less than 45°) is always present for roundabouts with inscribed circle diameter less than 25 m;for urban roundabouts with refuge islands for pedestrians and cyclists having inscribed circle diameter less than34 m and orthogonal legs;and for roundabouts with angles between opposite legs smaller than 140°. The main parameters which are responsible for a decrease in the deviation angle are: a decrease in the inscribed circle diameter;a decrease in the angle between opposite legs;and an increase in the width of the circulatory lane. Some optimized procedures for roundabout design, the generalized application of the deviation angle method and alternative speed control measures in cases of small deviation angles are discussed.

关键词： Traffic engineering One-lane roundabout Roundabout deflection deviation angle Speed control

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A Statistical Model of Quantitative Relationship between Striation Spacings and Fatigue Crack Growth Rates

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Journal of Materials Science & Technology 1989年第6期5卷 407-411页

作者：杨京俊柯伟 Institute of Corrosion and Protection of Metals Academia Sinica Shenyang China. To whom correspondence should be addressed Institute of Corrosion and Protection of Metals Academia Sinica Shenyang China

Fatigue crack growth experiments were per- formed on A1 alloy LD 10 and Ti-6A1-4V alloy. Fatigue striation spacings and the deviation angles between the direction of micro-crack growth and that of macro-crack growth were quanti- tatively measured on fracture surface using scanning electron microscope. A statistical model of the relationship between striation spacings and fatigue crack propagation rates was developed on the basis of a statistical analysis of the deviation angles, Good agreement between experimental results and theoretical results calculated with the present model was obtained.

关键词： striation spacing deviation angle fatigue crack growth

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Designing an Automated Tractor and Semi-trailer Exchange System for Drop and Pull Transport

Designing an Automated Tractor and Semi-trailer Exchange Sys...

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第30届中国控制与决策会议

作者： Luhua Zhao Entong Wang Yang Li Xinyu Dou College of Transportation Shandong University of Science ＆ Technology

This paper aims at designing an automated exchange system for tractor and semi-trailer. The design is based on the analysis of the current exchange system and the autonomous truck system. The purpose of this design is to improve both the efficiency of exchanging and the development of drop and pull tractor. Based on the technology of sensors and information, the designed functions are realized based on two parameters reflecting errors: 1) the deviation angle between the center-line of a tractor and that of a semi-trailer;2) the distance between the upper plane of fifth wheel and the lower plane of hauling pin. The two parameters are collected and fed into a master computer which analyzes the errors and asks automated control parts to make adjustments on the errors. The automated tractor and trailer exchange system can save the effort of manual operations, automate the complex processes, and reduce the failure rate in the exchanging process. This automated system has significant improvement on the perspectives of safety and practicality. The model simulation and analysis based on SOLIDWORKS show that the system designed in this paper is feasible and has strong practical significance in safety and practicability.

关键词： Automated Tractor and Semi-trailer Exchange System Efficiency Issues deviation angle Height Difference

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