Research on the Critical Technique of Synchronous Rotation Construction With Large Angle for T-shape Curve Rigid Frame Bridge

2021 ◽  
Author(s):  
Junhu Shao ◽  
Mengjun Duan ◽  
Wei Yang
Keyword(s):  
Friction Coefficient ◽  
Traffic Safety ◽  
Control Method ◽  
Large Angle ◽  
Static Friction ◽  
Test Method ◽  
Rigid Frame ◽  
Synchronous Rotation ◽  
Traction System ◽  
Shape Curve

Abstract The superstructure rotation method (SRM) can optimize bridge construction in terms of reducing impacts on traffic, safety, and overall budget. This paper focuses on the key scientific problems of synchronous rotation construction with large angles and takes two T-shaped rigid frame bridges of the Wuyi Expressway over the Chengdu-Kunming Railway as the engineering background. Construction technologies of this project are introduced, including the installation process of spherical hinges, the design of the traction system, and the precision control method. Finite element models of the full-bridge were established to obtain the lateral unbalanced moment of the structure and the test method of the longitudinal unbalanced moment is shown in detail. Furthermore, the key parameters of SRM are analyzed and calculated, including the derivation and modification of the existing static friction coefficient calculation formula of the spherical hinge. Based on the measured data, the accuracy of different friction coefficient prediction formulas is evaluated.

Investigations of Road Wear Caused by Studded Tires

2014 ◽  
Vol 42 (1) ◽  
pp. 2-15
Author(s):  
Johannes Gültlinger ◽  
Frank Gauterin ◽  
Christian Brandau ◽  
Jan Schlittenhard ◽  
Burkhard Wies
Keyword(s):  
Traffic Safety ◽  
Test Bench ◽  
Operating Conditions ◽  
Test Method ◽  
Analytical Models ◽  
The Road ◽  
Driving Speed ◽  
Major Factors ◽  
Tire Friction ◽  
Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

Measurements of the Static Friction Coefficient Between Tin Surfaces and Comparison to a Theoretical Model

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Rebecca D. Ibrahim Dickey ◽  
Robert L. Jackson ◽  
George T. Flowers
Keyword(s):  
Theoretical Model ◽  
Friction Coefficient ◽  
Human Error ◽  
Surface Profile ◽  
Static Friction ◽  
Quantitative Agreement ◽  
High Plasticity ◽  
Static Friction Coefficient ◽  
Experimental Apparatus ◽  
Rough Surface Contact

A new experimental apparatus is used to measure the static friction between tin surfaces under various loads. After the data is collected it is then compared to an existing theoretical model. The experiment uses the classical physics technique of increasing the incline of a plane and block until the block slides. The angle at the initiation of sliding is used to find the static friction coefficient. The experiment utilizes an automated apparatus to minimize human error. The finite element based statistical rough surface contact model for static friction under full stick by Li, Etsion, and Talke (2010, “Contact Area and Static Friction of Rough Surfaces with High Plasticity Index,” ASME Journal of Tribology, 132(3), p. 031401) is used to make predictions of the friction coefficient using surface profile data from the experiment. Comparison of the computational and experimental methods shows similar qualitative trends, and even some quantitative agreement. After adjusting the results for the possible effect of the native tin oxide film, the theoretical and experimental results can be brought into reasonable qualitative and quantitative agreement.

scholarly journals Brittle Fracture Theory Describes the Onset of Frictional Motion

2019 ◽  
Vol 10 (1) ◽  
pp. 253-273 ◽  
Author(s):  
Ilya Svetlizky ◽  
Elsa Bayart ◽  
Jay Fineberg
Keyword(s):  
Friction Coefficient ◽  
Brittle Fracture ◽  
Static Friction ◽  
Quantitative Agreement ◽  
Interface Fracture ◽  
Earthquake Dynamics ◽  
Rupture Dynamics ◽  
Static Friction Coefficient ◽  
Fracture Theory ◽  
Macroscopic Motion

Contacting bodies subjected to sufficiently large applied shear will undergo frictional sliding. The onset of this motion is mediated by dynamically propagating fronts, akin to earthquakes, that rupture the discrete contacts that form the interface separating the bodies. Macroscopic motion commences only after these ruptures have traversed the entire interface. Comparison of measured rupture dynamics with the detailed predictions of fracture mechanics reveals that the propagation dynamics, dissipative properties, radiation, and arrest of these “laboratory earthquakes” are in excellent quantitative agreement with the predictions of the theory of brittle fracture. Thus, interface fracture replaces the idea of a characteristic static friction coefficient as a description of the onset of friction. This fracture-based description of friction additionally provides a fundamental description of earthquake dynamics and arrest.

Numerical Investigation of the Influence of Friction Coefficient on Brake Groan

2010 ◽  
Vol 44-47 ◽  
pp. 1923-1927 ◽  
Author(s):  
Xian Jie Meng
Keyword(s):  
Nonlinear Dynamics ◽  
Friction Coefficient ◽  
Degrees Of Freedom ◽  
Equilibrium Points ◽  
Static Friction ◽  
Kinetic Friction ◽  
Dynamics Model ◽  
Excited Vibration ◽  
Nonlinear Dynamics Model ◽  
The Stability

A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the stability of vibration system at the equilibrium points is analyzed using the nonlinear dynamics theory. Finally the numerical method is taken to study the impacts of friction coefficient on brake groan. The calculation result shows that with the increase of kinetic friction coefficient /or the decrease of difference value between static friction coefficient and kinetic friction coefficient can prevent or restrain self-excited vibration from happening.

The Analysis and Assessment of Test Method for Flammability of an Automotive Headlining Fabric

2011 ◽  
Vol 332-334 ◽  
pp. 1162-1166
Author(s):  
Zhuo Zhang ◽  
Ying Qing Liu ◽  
Zhong Hai Ren ◽  
Jia Zhuang Ma ◽  
Hu Shui Ye
Keyword(s):  
Traffic Safety ◽  
Test Method ◽  
Highway Traffic ◽  
National Highway Traffic Safety ◽  
Test Standards ◽  
Foreign Countries ◽  
Mandatory Standard ◽  
Testing Standards ◽  
Interior Textile ◽  
Automotive Interior

The flammability is one of the most important features about safety for automotive interior material. This paper summarized the testing standards for flammability performed testing on a type of interior textile material made by one of domestic manufacturers, in accordance with the Chart 571.302 Standard No. 302 of the National Highway Traffic Safety Administration of U.S. The complete introduction of national mandatory standard of China in flammability of interior material was introduced and domestic test standards of flammability with those of foreign countries all over world were compared. Finally, this paper proposed possible and would-be necessary parameters based on comprehensiveness of this kind of test due to safer requirement in future.

scholarly journals Adaptive Neural Network Control of Zero-Speed Vessel Fin Stabilizer Based on Command Filter

2022 ◽  
Vol 12 (2) ◽  
pp. 754
Author(s):  
Ziteng Sun ◽  
Chao Chen ◽  
Guibing Zhu
Keyword(s):  
Neural Network ◽  
Control System ◽  
Control Method ◽  
Large Angle ◽  
Network Control ◽  
Neural Network Control ◽  
Adaptive Neural Network ◽  
Adaptive Neural Network Control ◽  
Command Filter ◽  
Fin Stabilizer

This paper proposes a zero-speed vessel fin stabilizer adaptive neural network control strategy based on a command filter for the problem of large-angle rolling motion caused by adverse sea conditions when a vessel is at low speed down to zero. In order to avoid the adverse effects of the high-frequency part of the marine environment on the vessel rolling control system, a command filter is introduced in the design of the controller and a command filter backstepping control method is designed. An auxiliary dynamic system (ADS) is constructed to correct the feedback error caused by input saturation. Considering that the system has unknown internal parameters and unmodeled dynamics, and is affected by unknown disturbances from the outside, the neural network technology and nonlinear disturbance observer are fused in the proposed design, which not only combines the advantages of the two but also overcomes the limitations of the single technique itself. Through Lyapunov theoretical analysis, the stability of the control system is proved. Finally, the simulation results also verify the effectiveness of the control method.

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