Dynamic response of electromagnetic railgun due to projectile movement

Tzeng, Jerome T.

doi:10.1109/tmag.2002.806384

Cited by 75 publications

(27 citation statements)

References 4 publications

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“…Meanwhile, gouging only takes place when it reaches a certain gouge velocity threshold [6] which is quite close to the rail resonance's [7][8][9] , in consequence, the partial deflection caused by resonance may be the key factor for generating gouging.…”

Section: A Equations Of Dynamic Responsementioning

confidence: 99%

Impact physics model and influencing factors of gouging for electromagnetic rail launcher

Zhu

Zhang

et al. 2014

2014 17th International Symposium on Electromagnetic Launch Technology

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Gouging is a damage mechanism that occurs on the surface of rails of electromagnetic railgun. The disadvantages of gouging include lowering efficiency of railgun system, decreasing life of rails and reducing direction accuracy of projectile. According to configuration and dimension of the experimental arrangement, analysis of rail vibration induced by hypervelocity sliding load and numerical solve of the dynamic response for rails have been accomplished. Based on numerical solve of the dynamic response for rails under hypervelocity sliding load, a gouging physics model of impact has been established in this paper, and gouging on the rail was successfully replicated in LS-DYNA. Through dynamic simulating, effect rule of influencing factors such as deflection bulge size on the formation of gouging and key phenomenon of gouge process were investigated. The results suggested that the obvious gouging would be avoided by lowering the maximal local deflection size in 0.5mm; the structure of smooth on the head of the armature and decrease of contact pressure between armature and rails can be utilized to alleviate the damage; during gouging process, maximal strain-rate of rail material could reach to 10 7 s -1 while the contact area and velocity of armature would fell greatly. This work would be a foundation of future effort of avoiding rail gouging during the launch duration.

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Section: A Equations Of Dynamic Responsementioning

confidence: 99%

Impact physics model and influencing factors of gouging for electromagnetic rail launcher

Zhu

Zhang

et al. 2014

2014 17th International Symposium on Electromagnetic Launch Technology

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“…The critical velocity can also be evaluated according to beam theory [5]. In our case, the rail structure may be considered as a T-shaped composite beam characterized by effective parameters, and as a result, may be expressed as follows:…”

Section: B Dynamic Behavior Under Constant Velocitymentioning

confidence: 99%

“…Analytical treatment of the beam under moving point loads and the simplest solutions are presented in the book by Fryba [4]. An analytical approach to the investigation of the dynamic response of laboratory railguns, including projectile movement, was developed in a number of works by Tzeng [5] and Tzeng and Sun [6]. The rail was modeled as a cantilever beam on an elastic foundation.…”

Section: Introductionmentioning

confidence: 99%

Structural Mechanics of Railguns in the Case of Discrete Supports

et al. 2009

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In this paper, numerical calculations concerning the dynamic behavior of a railgun are presented. At the first stage, the structural problem can be decoupled from electromagnetic phenomena as well as from the local projectile behavior. The magnetic pressure repelling the rails from each other and expanding with the speed of the projectile serves as a boundary condition for purely mechanical calculations. The particularity of the investigation is represented by the type of railgun housing. For some years, the ISL has been using laboratory housings of an open design allowing, for instance, to take flash radiographs during launch. The repelling forces are mainly taken by discrete supports in the form of steel bolts. These bolts are connected to bars made of glassfiber-reinforced plastics, while the rails are mounted on these bars. A 2-D finite-element model of a complex housing was developed in this paper. Bars, including rails, are described by plane-stress elements, while bolts, playing the role of discrete elastic supports, are presented by truss elements. The model is implemented using the ANSYS code. Deformation properties of the rail section and elastic supports are examined by considering a static solution, assuming constant loading. Differences between 2-D and conventional beam models being of importance for this kind of problem are briefly discussed. Transient analysis was performed for a set of constant loading velocities (600-1600 m/s) and for the experimentally derived transient-loading profile. The latter was obtained in the railgun experiments performed using the ISL-railgun EMA3 with a caliber of 15 30 mm 2 and typical muzzle velocities up to 1600 m/s as well as peak currents of about 600 kA.Index Terms-Discrete elastic supports, electromagnetic railgun, finite-element (FE) method, transient dynamics.

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“…Both theoretical and experimental investigations on the railgun have been widely developed over the last three decades. [1][2][3][4][5] The solid-armature railgun and plasma-armature railgun are two typical EMLs. The former has the advantages of low resistance, low muzzle voltage, and high transformation rate; however, the muzzle velocity of this railgun is mostly less than 2km/s.…”

Section: Introductionmentioning

confidence: 99%

“…The former has the advantages of low resistance, low muzzle voltage, and high transformation rate; however, the muzzle velocity of this railgun is mostly less than 2km/s. As the armature reaches to a critical velocity [3,4] , the transition is an outcome of imperfect electrical contacts due to drastic ohmic heating (resulting in the velocity skin effect) on the armature-rail interface. Plasma armature, in general produced by a metal foil (e.g.…”

Section: Introductionmentioning

confidence: 99%

Structure Design of an "Open-Bore" Electromagnetic Launcher

Nie

Jiao

Qin

et al. 2008

2008 14th Symposium on Electromagnetic Launch Technology

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An "open-bore" railgun, a small bore of 14 mm with vented top and bottom, was designed especially for the Beijing Institute of Technology Armature Tester (BITAT) Electromagnetic Launcher (EML) Program. This novel design may be a possible solution to avoiding forming "secondary arc", and will be mainly employed as a plasma armature tester in the near future. In this paper, a series of numerical simulations on the structural strength and deformation of our railgun are investigated by using the finite element method. A simple plate-mechanics model is also proposed to evaluate the maximum permissible EM force on the insulated support plates. Finally, the optimum design of our railgun is suggested based on the results of the numerical simulations.

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Dynamic response of electromagnetic railgun due to projectile movement

Cited by 75 publications

References 4 publications

Impact physics model and influencing factors of gouging for electromagnetic rail launcher

Impact physics model and influencing factors of gouging for electromagnetic rail launcher

Structural Mechanics of Railguns in the Case of Discrete Supports

Structure Design of an "Open-Bore" Electromagnetic Launcher

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