Characterization of the Velocity Skin Effect in the Surface Layer of a Railgun Sliding Contact

Engel, T.G.; Neri, J. M.; Veracka, M.J.

doi:10.1109/tmag.2008.922310

Cited by 84 publications

(30 citation statements)

References 15 publications

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“…Hsieh et al [7] drew a conclusion that a 3-D model simulation on the parameters of hypervelocity railgun could work well only when the velocity was less than 500 m/s. Engel et al [8] used quantum tunneling effect of a 40-120-nm-thick oxide layer to evaluate the velocity saturation and efficiency roll-off because of VSE.…”

Section: Introductionmentioning

confidence: 99%

Physical Principle and Relevant Restraining Methods About Velocity Skin Effect

Xiang

Lei

et al. 2015

IEEE Trans. Plasma Sci.

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Velocity skin effect (VSE) is a kind of current clustering phenomenon, which occurs at the sliding contact interfaces between the high-speed armature and the stationary rails of electromagnetic railgun launchers. Serious current clustering is disadvantageous to the launching performance. The typical current clustering phenomena in static conductors are classified, and the physical principle of VSE is analyzed in this paper. The physical principle in rails is just skin effect because of the short rise time of the accepted pulse current, and the physical principles in armature are clustering near small source and clustering along short path of steady current owing to the continuity characteristic or Laplace equation. The corresponding methods to restrain VSE are deduced and classified as follows: 1) lengthening the contact surface; 2) adding a hard and resistive cladding on the rail's sliding surface; 3) narrowing the interface; 4) adopting a U-shaped armature instead of cuboid one; and 5) controlling the armature legs' thickness/width distribution. An equivalent 3-D model for VSE is adopted, and simulation is carried out for a complex form of armature leg. The uniform current in the interfaces is accomplished, with which the typical uniform index is about 66%. VSE is restrained according to the simulation result. The physical principle, the relevant restraining methods, and the equivalent model are significant to railgun research work.

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Section: Introductionmentioning

confidence: 99%

Physical Principle and Relevant Restraining Methods About Velocity Skin Effect

Xiang

Lei

et al. 2015

IEEE Trans. Plasma Sci.

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“…Velocity skin effect (VSE) [1][2] is a kind of current clustering phenomenon, which occurs at the sliding contact interfaces between armature and rail of railgun at hypervelocity. When the armature slides on the rail with hypervelocity, the current flowing across the interface trends to cluster in the rear part, especially on the rear perimeter edges.…”

Section: Introductionmentioning

confidence: 99%

On velocity skin effect — Part II: Restraining method analysis and optimal design simulation

Lei

et al. 2014

2014 17th International Symposium on Electromagnetic Launch Technology

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Velocity skin effect (VSE) is a kind of current clustering phenomenon, which occurs in the sliding contact interfaces between the hypervelocity armature and the stationary rails for electromagnetic railgun, disadvantageous to launchers performance. The physical principle of VSE is Skin Effect of pulsed current in rails, and Clustering Near Small Source and Clustering Along Short Path of steady current in armature. The corresponding methods to restrain VSE was deduced and classified in this paper as the followings: 1) to lengthen the contact surface according to the velocity skin depth expression, 2) to add a hard and resistive cladding on the rail's sliding surface and 3) to narrow the interface considering the Clustering Near Small Source, 4) to adopt U-shaped armature instead of cuboid armature and 5) to control the armature legs' thickness distribution owing to Clustering Along Short Path. The equivalent 3-D models for VSE were adopted and the contrastive simulations were carried out for three kinds of armature's legs. The most uniformed distribution of current in three interfaces was accomplished, with which the typical uniform index is about 66%. The conclusion reached was that the general use of five methods and reasonable design could effectively restrain velocity skin effect.

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“…The influence factors of the friction and wear in the pantograph catenary system are: contact pressure, contact current, the speed of the Motor vehicle and so on. The intercoupling of the factors will also affect each other and then influence the wear, which is involved in electric erosion wear and mechanism wear [3][4][5]. Qualitative analysis is major research method in recent days.…”

Section: Introductionmentioning

confidence: 99%

Modeling study of the amount of wear in sliding electric contact

Chen

Hui

Wang

et al. 2012

26th International Conference on Electrical Contacts (ICEC 2012)

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The wear produced from the sliding contact in the pantograph slide and contact line system, has a direct relationship with the contact load. In premise of the current carrying performance conditions, there will be erosion resistance wear when the load is smaller, but mechanism wear when the load is bigger. In this article, many experiments through the leaching copper carbon sliding plate and Silver copper wire were conducted to study the wear characteristics of the sliding electrical contact in different load flow, speed and the changes of load. And some variables are fixed, then the others will be changed to find the variety of wear, also the data have been saved. After analyzing the relationship of different conditions, a model including the wear and the contact load will be produced, then draw the function equation include speed and others variables. The coefficient of which will be devised based on the saved data using the least-square method. And some experimentations are taken to validate the model, which could adequately reflect the function relationship between the wear and contact load. Also this model will be given a theory basis on the best load designing.

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Characterization of the Velocity Skin Effect in the Surface Layer of a Railgun Sliding Contact

Cited by 84 publications

References 15 publications

Physical Principle and Relevant Restraining Methods About Velocity Skin Effect

Physical Principle and Relevant Restraining Methods About Velocity Skin Effect

On velocity skin effect — Part II: Restraining method analysis and optimal design simulation

Modeling study of the amount of wear in sliding electric contact

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Characterization of the Velocity Skin Effect in the Surface Layer of a Railgun Sliding Contact

Cited by 84 publications

References 15 publications

Physical Principle and Relevant Restraining Methods About Velocity Skin Effect

Physical Principle and Relevant Restraining Methods About Velocity Skin Effect

On velocity skin effect &#x2014; Part II: Restraining method analysis and optimal design simulation

Modeling study of the amount of wear in sliding electric contact

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Product

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On velocity skin effect — Part II: Restraining method analysis and optimal design simulation