Theoretical Design and Modeling of an Infantry Railgun Projectile

Theoretical Design and Modeling of an Infantry Railgun Projectile
Author:
Publisher:
Total Pages: 126
Release: 2005
Genre: Physics
ISBN:

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In order for railgun technology to be relevant to the Infantry, the design of the projectile must incorporate the following three concepts: an effective ballistics package, geometries for aerodynamic stability; and a non-parasitic conducting armature. I designed an effective 30mm and scaled 40mm projectile which incorporates the aforementioned concepts. My ballistics analysis concluded with two AUTODYN(Trademark) finite-element computer models that refined theoretical estimates for target penetration. The proposed railgun projectiles were effective in penetrating 100 mm of Rolled Homogenous Armor and in perforating 8 inches of Double Layered Reinforced Concrete. My theoretical analysis in aerodynamics predicts in-flight stability with a minimum static margin of approximately two percent. The analysis and modeling of the electromagnetic launch resulted in an adequate design. For this analysis, I used three Comsol Multiphysics(Trademark) finite-element computer models. The modeling results validated fundamental railgun equations. The final projectile design concluded with a 3 m barrel and is characterized by the following parameters: conducting rails with an inductance gradient approximately equal to 0.38 H/m; an average temperature rise in the rails of 20 C per shot; an effective current of less than 2 MA; and a projectile launch velocity of 1100 m/s.

Computational Ballistics III

Computational Ballistics III
Author: C. A. Brebbia
Publisher: WIT Press
Total Pages: 257
Release: 2007
Genre: Technology & Engineering
ISBN: 1845640772

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Containing the proceedings of the Third International Conference on Computational Ballistics, this book presents new ideas and advanced developments in the field of study of Computational Ballistics. Ballistic studies include applications as varied as the study of the structural and control behavior of rockets and communication satellites; bird strike effects on commercial aircraft, terrorist attacks and automobile crack worthiness modelling. Many basic problems of ballistics are similar to those in other fields of applications, such as combustion, heat conduction, in-flight structural behaviour, trajectory related issues, contact, impact, penetration, structural response to shock waves and many others.A valuable contribution to its field, this text will be of interest to researchers involved in the different areas of computational ballistics and their relationship between computational methods and experiments. Notable topics include: Systems and Technolog; Combustion and Heat Transfer; Propellants; Fluid Dynamics; Fluid Flow and Aerodynamics; In-Flight Structural Behaviour and Material Response; Guidance and Control; Perforation and Penetration Mechanics; Fluid-structure Interaction; Experimental Mechanics/ballistic and Field Testing; High Rate Loads; Composite Material; Shock and Impact.

Design, Fabrication, and Testing of a Scalable Series Augmented Railgun Research Platform

Design, Fabrication, and Testing of a Scalable Series Augmented Railgun Research Platform
Author:
Publisher:
Total Pages: 119
Release: 2006
Genre: Laser peening
ISBN:

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The design and material properties of rails and projectiles are critical to the success of the Navy railgun. This thesis addresses the design, fabrication, and testing of a scalable square bore electromagnetic railgun. This railgun is designed to permit series augmented operation, and incorporates disposable rail liners to facilitate investigating the suitability of various rail materials. A series of shots has demonstrated performance consistent with theoretical modeling, including significant performance enhancement as a result of both slotted rail geometry and augmentation over solid rail and un-augmented configurations. A capacitor based stored energy supply input of 35 kJ resulted in a measured velocity of 294 m/s for an 11.4 gram projectile. Suggestions are provided for future power supply configurations, rail materials and surface treatments, and a variety of armature geometries.

Basic Simple Modeling of In-Bore Motion of Railgun Projectiles

Basic Simple Modeling of In-Bore Motion of Railgun Projectiles
Author:
Publisher:
Total Pages: 17
Release: 1991
Genre:
ISBN:

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In an electromagnetic railgun a projectile encounters a complex force environment during launch. A thorough understanding of these forces is critical to projectile and gun tube design. There are many parameters involved and interacting relationships which must be determined. To better understand and establish the in-bore force models, we begin with a basic simple model which computes only the axial motion. More complicated models will be introduced in subsequent reports which will include lateral forces and gun tube vibration effects. This report deals with a very simple axial motion model. Only the effects of the propulsion force, projectile package mass, air resistance, and the friction forces are presented. Equations of motion are derived and solved. A sample computation with available data is performed and curves plotted to give clearer understanding of the results.

Theoretical Problems Concerning Railgun Design

Theoretical Problems Concerning Railgun Design
Author: Richard L. Liboff
Publisher:
Total Pages: 87
Release: 1986
Genre:
ISBN:

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Various theoretical studies associated with design and implementation of a railgun are presented. Among other items the report contains a new equation of state for a strongly coupled laboratory plasma as well as a new analytic expression for electrical conductivity for a strongly coupled plasma. A fully relativistic analysis is made of the dynamics of a rail-gun based three assumptions: (1) Ohm's law is valid in the rest frame of the plasma; (2) total electron momentum is transferred to the projectile; and (3) motion of the projectile is constrained to one direction. With these assumptions, a relativistic equation for the velocity of the projectile is obtained whose solution monotonically increases to one of two values depending on field strengths. For B> E, the maximum velocity is cE/B whereas for E> B it is c where c is the speed of light, and E and B are applied electric and magnetic fields, respectively (in cgs).

A Projectile for a Rectangular Barreled Rail Gun

A Projectile for a Rectangular Barreled Rail Gun
Author: Francisco M. Juanche
Publisher:
Total Pages: 98
Release: 1999-12-01
Genre:
ISBN: 9781423540328

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The Physics Department at the Naval Postgraduate School is developing a concept to overcome the problems that keep present rail guns from being practical weapons. The rails must be replaced often if the rail gun operation is to be continuous. Replacing the rails in present rail gun configurations is time consuming. The Physics Department's design concept uses a rectangular barrel as part of the solution to the problem of replacing the rails. The projectile will require flat surfaces to maintain electrical contact with the flat rails and aerodynamic stabilization because of the lack of angular momentum. This thesis develops one possible model of a projectile for a rectangular barreled rail gun, which could be used to replace the standard five-inch gun found on most warships. The proposed projectile is successfully modeled as a five inch projectile with flat areas planed onto opposite sides and long chord, short span fins attached in a cruciform configuration. The computer programs used to develop the projectile model are included to allow evaluation of alternate configurations.

Basic Simple Modeling of Balloting Motion of Railgun Projectiles

Basic Simple Modeling of Balloting Motion of Railgun Projectiles
Author:
Publisher:
Total Pages: 23
Release: 1991
Genre:
ISBN:

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This is the second of three basic reports dealing with the in-bore balloting motion of a projectile launched in an electromagnetic railgun. The first report addressed axial projectile motion without cocking and was titled 'A Basic Single Model of In-bore Motion of Railgun Projectiles.' Understanding the inbore motion of a projectile is important to its design and its ability to hit a target with some effectiveness. Analysis of in-bore motion is a complicated problem since many parameters are involved and the interacting relationships between them must be determined. To make the problem easier to understand, it was analyzed on several levels beginning with the basic simple model which computed only the axial motion and followed by more complicated models in the upper analysis levels that included as many lateral forces and gun tube vibration effects as possible. This report deals with the second basic or zero level of balloting analysis. A basic simple model considering only the effect of the propulsion force, the friction force of the armature, and the clearance between the projectile and the barrel is presented. The computation of the axial projectile motion with a certain cocking angle is the goal of this analysis. Equations of motion are derived and solved. A sample computation with available data is performed and the results plotted to give a clearer understanding of balloting action.

An Approximate Analysis of Balloting Motion of Railgun Projectiles

An Approximate Analysis of Balloting Motion of Railgun Projectiles
Author:
Publisher:
Total Pages: 26
Release: 1991
Genre:
ISBN:

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This is the final of three reports dealing with the in-bore balloting motion of a projectile fired from an electromagnetic railgun. Knowledge of projectile in-bore motion is important to its design and the design of the railgun. It is a complicated problem since many parameters are involved and it is not easy to determine the interacting relationships between them. To make the problem easier to understand it was analyzed on several levels. Beginning from the basic simple model which computed only the axial motion, more complicated models were introduced in upper levels that included the more significant lateral forces and gun tube vibration effects. This report deals with the approximate analysis of balloting motion. This model considers the effects of the propulsion force, the friction force of the projectile package (projectile and armature), air resistance, gravity, the elastic forces, and the projectile/ barrel clearance. To simplify the modeling, a plane motion configuration is assumed. Though the projectile is moving with a varying yaw angle, the axes of the barrel and the projectile package, and the projectile center of gravity are always considered in a plane containing the centerlines of the rails. Equations of motion are derived and solved. A sample computation is performed and the results plotted to give a clearer understanding of projectile in-bore motion.

Electrical and Thermal Modeling of Railguns

Electrical and Thermal Modeling of Railguns
Author:
Publisher:
Total Pages:
Release: 1983
Genre:
ISBN:

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Electrical and thermal modeling of railguns at Los Alamos has been done for two purposes: (1) to obtain detailed information about the behavior of specific railgun components such as the rails, and (2) to predict overall performance of railgun tests. Detailed electrical and thermal modeling has concentrated on calculations of the inductance and surface current distribution of long parallel conductors in the high-frequency limit and on calculations of current and thermal diffusion in rails. Inductance calculations for various rail cross sections and for magnetic flux compression generators (MFCG) have been done. Inductance and current distribution results were compared with experimental measurements. Two-dimensional calculations of current and thermal diffusion in rail cross sections have been done; predictions of rail heating and melting as a function of rail size and total current have been made. An overall performance model of a railgun and power supply has been developed and used to design tests at Los Alamos. The lumped-parameter circuit model uses results from the detailed inductance and current diffusion calculations along with other circuit component models to predict rail current and projectile acceleration, velocity, and position as a function of time.