Measuring Model of Dynamic Contact Force

2012 ◽  
Vol 503-504 ◽  
pp. 1614-1618
Author(s):  
Zhong Guo Sun ◽  
Xiang Dong Li ◽  
Wei Dong Wang
Keyword(s):  
Contact Force ◽  
High Speed ◽  
Dynamic Contact ◽  
Overhead Line ◽  
Mass Correction

There are no systematic studies reported on measuring model of dynamic contact force between pantograph and overhead line. Keep this in view, the high-speed measuring model of dynamic contact force between pantograph and overhead line is discussed in details in this article. Based on the analysis of forces acting on the pantograph, measuring model of dynamic contact force is constructed with the mass correction and aerodynamic compensation. The results of verifying running test are given in the end of article to show that the measuring model is effective practically.

Computer Evaluation of Controlled Pantographs for Current Collection From Simple Catenary Overhead Equipment at High Speed

1983 ◽  
Vol 105 (4) ◽  
pp. 287-294 ◽  
Author(s):  
T. Vinayagalingam
Keyword(s):  
Contact Force ◽  
High Speed ◽  
Overhead Line ◽  
Combined System ◽  
Current Collection ◽  
Constant Height ◽  
Force Profile ◽  
Force Variation ◽  
Computer Simulation Technique

A digital computer simulation technique is used to study the effects of changing pantograph characteristics upon the quality of current collection from simple catenary overhead equipment at high speed. In particular, the likely benefits to be derived by the use of controlled pantographs are assessed. Pantograph performance is judged on the basis of contact force variation and displacement responses of pantograph and contact wire. These studies have shown that the dynamic displacements of the combined system are determined primarily by the overhead line parameters rather than by the pantograph. At higher speeds droppers in the vicinity of the pantograph slacken and this is seen to influence significantly the contact force profile. On a “constant height” overhead line, the proposed “frame compensated” and “panhead inertia compensated” pantographs do not show any marked improvement in the quality of current collection.

scholarly journals Effect of Pantograph’s Main Structure on the Contact Quality in High-Speed Railway

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiangwen Wang ◽  
Guiming Mei
Keyword(s):  
Contact Force ◽  
Structural Design ◽  
High Speed ◽  
Electrical Energy ◽  
Dynamic Contact ◽  
Sine Series ◽  
High Speed Railway ◽  
Main Structure ◽  
Current Collection ◽  
Relative Coordinates

In general, the electrical energy is provided to the high-speed train through the pantograph-catenary sliding contact. The variation of the dynamic contact force is expected to be small enough to keep the good current collection quality and to extend the service life of the pantograph-catenary system. In this paper, the two tension wires of the catenary are discretized by the sine-series expansions, a multibody dynamics theory based on relative coordinates is adopted to describe the dynamic behavior of the pantograph, and the standard deviation (STD) of dynamic contact force is used as the indicator to evaluate the contact quality. The objective is to investigate how the variations of the pantograph’s main structure influence the contact quality, which may support the structural design and parameter optimization of the pantograph in high-speed railway.

Characteristics of air entrainment during dynamic wetting failure along a planar substrate

2014 ◽  
Vol 747 ◽  
pp. 119-140 ◽  
Author(s):  
E. Vandre ◽  
M. S. Carvalho ◽  
S. Kumar
Keyword(s):  
High Speed ◽  
Water Solution ◽  
Air Entrainment ◽  
Dynamic Contact ◽  
Operating Conditions ◽  
Dynamic Wetting ◽  
Glycerol Water ◽  
Planar Substrate ◽  
Wide Range ◽  
Stationary Plate

AbstractCharacteristic substrate speeds and meniscus shapes associated with the onset of air entrainment are studied during dynamic wetting failure along a planar substrate. Using high-speed video, the behaviour of the dynamic contact line (DCL) is recorded as a tape substrate is drawn through a bath of a glycerol/water solution. Air entrainment is identified by triangular air films that elongate from the DCL above some critical substrate speed. Meniscus confinement within a narrow gap between the substrate and a stationary plate is shown to delay air entrainment to higher speeds for a wide range of liquid viscosities, expanding upon the findings of Vandre, Carvalho & Kumar (J. Fluid Mech., vol. 707, 2012, pp. 496–520). A pressurized liquid reservoir controls the meniscus position within the confinement gap. It is found that liquid pressurization further postpones air entrainment when the meniscus is located near a sharp corner along the stationary plate. Meniscus shapes recorded near the DCL demonstrate that operating conditions influence the size of entrained air films, with smaller films appearing in the more viscous solutions. Regardless of size, air films become unstable to thickness perturbations and ultimately rupture, leading to the entrainment of air bubbles. Recorded critical speeds and air-film sizes compare well to predictions from a hydrodynamic model for dynamic wetting failure, suggesting that strong air stresses near the DCL trigger the onset of air entrainment.

Evaluation of vehicular contact force on bridge joints by vibration responses and object detection

2021 ◽  
Author(s):  
Di Su ◽  
Yuichiro Tanaka ◽  
Tomonori Nagayama
Keyword(s):  
Object Detection ◽  
Contact Force ◽  
Dynamic Contact ◽  
Contact Forces ◽  
Expansion Joints ◽  
Cyclic Movements ◽  
Bridge Joints ◽  
Vibration Responses ◽  
On The Road ◽  
Board System

<p>Expansion joints on bridges should accommodate cyclic movements to minimize imposition of secondary stresses in the structure. However, these joints are highly susceptible to severe and repeated vehicular impact that results their inherent discontinuity. In this paper, a portable on- board system including accelerometers and a drive recorder to evaluate the vehicular contact force on bridge joints is proposed. First, from the acceleration responses of the vehicle, the contact force exerted on the road surface is estimated from a half-car model by Kalman Filter. Next, extraction of the expansion joints is performed by object detection from videos taken by the drive recorder. Finally, a relative comparison of the contact forces acting on joints is performed, with location identification on the map. The proposed system benefits to utilize the dynamic contact forces results from on-board system to detect the potential risky joints more precisely and efficiently.</p>

scholarly journals Capillary transfer of soft films

2020 ◽  
Vol 117 (10) ◽  
pp. 5210-5216 ◽  
Author(s):  
Yue Zhang ◽  
Mengtian Yin ◽  
Yongmin Baek ◽  
Kyusang Lee ◽  
Giovanni Zangari ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Analysis ◽  
Liquid Surface ◽  
Theoretical Models ◽  
Dynamic Contact ◽  
Surface Wetting ◽  
Motion Direction ◽  
Wetting Properties ◽  
Geometric Patterns ◽  
Solid Substrates

Existing transfer technologies in the construction of film-based electronics and devices are deeply established in the framework of native solid substrates. Here, we report a capillary approach that enables a fast, robust, and reliable transfer of soft films from liquid in a defect-free manner. This capillary transfer is underpinned by the transfer front of dynamic contact among receiver substrate, liquid, and film, and can be well controlled by a selectable motion direction of receiver substrates at a high speed. We demonstrate in extensive experiments, together with theoretical models and computational analysis, the robust capabilities of the capillary transfer using a versatile set of soft films with a broad material diversity of both film and liquid, surface-wetting properties, and complex geometric patterns of soft films onto various solid substrates in a deterministic manner.

scholarly journals In Situ Rubber-Wheel Contact on Road Surface Using Ultraviolet-Induced Fluorescence Method

2020 ◽  
Vol 10 (24) ◽  
pp. 8804
Author(s):  
Jhonni Rahman ◽  
Yutaka Shoukaku ◽  
Tomoaki Iwai
Keyword(s):  
Contact Area ◽  
High Speed ◽  
High Sensitivity ◽  
Dynamic Contact ◽  
Road Surface ◽  
Oxide Semiconductor ◽  
Small Scale ◽  
In Situ Observation ◽  
On The Road

This study examines the relationship between rubber-wheel and the contact area on the road surface. Ultraviolet-induced fluorescence microscopy was used to observe and measure the contact parts with pyranine as a dye solution. The high sensitivity to U.V. light makes it easy to distinguish contact and non-contact regions on a very small scale. The experiment was conducted in static and dynamic conditions to identify its influence on the apparent contact area of rubber-wheel and road surface. The in-situ observation of the contact area was captured and recorded using a high-speed digital camera with 1-inch a CMOS (complementary metal oxide semiconductor) sensor. Additionally, the contact area between rubber-wheel and road surface was measured using an analyzing software. The results show differences in static and dynamic contact conditions based on the operating parameters.

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