Dynamics of a High-Speed Sliding Power Collector in Consideration of Sliding Friction

1978 ◽  
Vol 100 (2) ◽  
pp. 242-250
Author(s):  
K. Yoshida ◽  
T. Shimogo
Keyword(s):  
High Speed ◽  
Sliding Friction ◽  
Contact Stiffness ◽  
Equivalent Linearization ◽  
High Speed Railway ◽  
Sliding Direction ◽  
Contact Points ◽  
Force Variation ◽  
Digital Simulations ◽  
Very High

Considering the sliding friction force produced between a contactor and a rigid collecting rail with a randomly wavy surface, the paper deals with the dynamics of a sliding power collector for a very-high-speed railway. An analytical model is formulated, which has two contact points and takes into account the pitching of a contactor, the stiffness of the sliding direction in a contactor support system, and the nonlinearity of the contact stiffness between a contactor and a rail. Mainly, the influences of the sliding friction and the contact stiffness on the dynamic characteristics, i.e., the contact force variation, the probability of contact break, etc., are investigated. The equivalent linearization technique is applied in the analysis. To verify the analytical results, digital simulations are carried out by preparing the artificial collecting rail wave.

Dynamics of a Current Collector for a High-Speed Railway

1975 ◽  
Vol 97 (2) ◽  
pp. 731-738
Author(s):  
Kazuo Yoshida ◽  
Katsushi Manabe ◽  
Taro Shimogo
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Current Collector ◽  
Experimental Investigations ◽  
High Speed Railway ◽  
Collector System ◽  
Train Speed ◽  
Proper Values ◽  
Very High ◽  
A Current

In this paper, a mathematical model of a collecting rail and collector system with sliding contactors is proposed for a current collector system of a very-high-speed railway. Its dynamic characteristics, especially the variation of contact force and the probability of contact break, are investigated by means of linear analysis. In order to prove the appropriateness of the linear model, the computer simulation and theoretical analysis are performed using a nonlinear model. Experimental investigations are also performed in order to examine the dynamic characteristics of the model. From these results, it is concluded that the probability of contact break can be kept to less than about 10 percent for a train speed of 500 km/hr by choosing the proper values of natural frequencies and damping ratios under constraints.

Comparative Analysis of Various Kinds Concrete Creep Prediction Models

2011 ◽  
Author(s):  
Jun-Qing Lei ◽  
Hang Xu ◽  
Li-Qun Zou
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Prediction Models ◽  
Concrete Creep ◽  
High Speed Railway ◽  
Railway Line ◽  
The Difference ◽  
Short Time ◽  
Very High

The ratio of bridges to High-speed Railway line in China is very high. The influence of concrete creep to bridge structure is very high, so it is necessary to study creep of concrete in depth. In this thesis, experimental data of four important regions in China are collected, and the curves of concrete creep are analyzed. While, by comparing the domestic and foreign curves of Concrete Creep Prediction Models, the difference between them could be found. In addition, the theory of long-term deformation of concrete obtained by short-time experiment, which is proposed by Professor Bazant is used. According to experimental data, the creep curves are fittd by regression method. Finally, the comparison between common prediction models and Bazants’ theory is carried out, it can be found that the regression value is closed to the measured value.

Dynamics of a Power Collector With Friction Dampers

1976 ◽  
Vol 98 (1) ◽  
pp. 306-311 ◽  
Author(s):  
K. Yoshida ◽  
T. Shimogo
Keyword(s):  
Contact Force ◽  
Coulomb Friction ◽  
High Speed ◽  
Equivalent Linearization ◽  
Friction Damper ◽  
Friction Forces ◽  
Friction Dampers ◽  
Force Variation ◽  
Optimal Values ◽  
The Mean

Using the friction damper, the construction of power collector for a very high-speed railway will be considerably simplified. In this paper, the power collector with friction dampers is considered, and its dynamic characteristics are analyzed by the equivalent linearization technique. The main purpose of this paper is to investigate the effects of Coulomb friction forces on the mean squared value of contact force variation between a contactor and a rigid collecting rail with a randomly wavy surface. A numerical example is presented, and the optimal values of Coulomb friction forces which minimize the probability that the contact force becomes negative are found as a result.

Effects of friction-based fixed bearings on the seismic vulnerability of a high-speed railway continuous bridge

2017 ◽  
Vol 21 (5) ◽  
pp. 643-657 ◽  
Author(s):  
Biao Wei ◽  
Tianhan Yang ◽  
Lizhong Jiang ◽  
Xuhui He
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Seismic Vulnerability ◽  
Sliding Friction ◽  
Relative Displacement ◽  
High Speed Railway ◽  
Displacement Capacity ◽  
Seismic Force ◽  
Track Bridge ◽  
Bridge System

The fixed bearings of high-speed railway continuous bridges were vulnerable during earthquakes, since they transferred most of the seismic force between the superstructure and the piers. A type of friction-based fixed bearing was used and would slide during strong earthquakes. The influence of this sliding friction action on the seismic vulnerability curves of different components in the track-bridge system was analyzed in this article. Results show that the sliding friction action of the fixed bearings can protect other components from severe damage under earthquakes. This phenomenon is more significant when the friction coefficient on the friction-based fixed bearings is reduced. However, it increases the seismic relative displacement of the fixed bearings themselves. Finally, a sufficiently large displacement capacity and an appropriate friction coefficient between 0.2 and 0.3 are almost the best combination for the friction-based fixed bearings, which can effectively protect all components of the track-bridge system, including the track structure, piers, piles, and friction-based fixed bearings themselves.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

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