Bėgių tipo atvirojo kanalo elektromagnetinės svaidyklės magnetomechaninio efekto tyrimas

The dissertation investigates the electromagnetic launcher electromagnetic properties and their influence on mechanical construction. The main object of research is open bore two rail construction electromagnetic launcher. The dissertation aims to investigate the distribution of electromagnetic forces and their influence over the electromagnetic launcher construction volume. The work presents five tasks such as the electromagnetic and mechanical model application of the numerical model. The first task is formulated to rewiev the literature. The next two tasks are formulated to calculate the distribution of electromagnetic forces throughout the electromagnetic launcher construction volume. The last two tasks investigate the effect of the forces distribution differences over the electromagnetic launcher construction. The dissertation work consists of an introduction, four chapters, general conclusion, references, a list of publications by the author on the topic of the dissertation, a summary in Lithuanian and five annexes. The introductory chapter discusses the research problem, relevance of the work, introduces the object of the research, formulates the aim and the tasks of the work, describes the research methodology, scientific novelty of the work, considers the practical significance of the work results and defensive statements. At the end of the introduction, the publications and reports published by the author of the dissertation and the structure of the dissertation are presented. Chapter 1 is devoted to review the electromagnetic launcher analyses methods in literature. A brief overview of the adaptation and development history of electromagnetic launchers are provided. At the end of the chapter, conclusions are formulated, and the tasks of the dissertation are refined. Chapter 2 presents the structure and parameters of the electromagnetic launcher. According to this type of launcher, the electromagnetic and mechanical models were developed. The mathematical model of each modeling and boundary conditions are described, and the conclusions are presented. Chapter 3 and 4 provide the results of electromagnetic and mechanical modeling. The dependence between electromagnetic and mechanical problems are described. Conclusions are presented at the end of both sections. 4 articles have been published on the topic of the dissertation in the scientific journals included in the Clarivate Analytics Web of Science list, one article is in conference materials in the Clarivate Analytics Web of Science Proceedings database, and two is in peer-reviewed international conferencing materials. 4 presentations on the subject of the dissertation have been given in conferences at national and international levels

Program: 2021 Undergraduate Mathematics Day

Schedule and general information about the event. 21st Annual Kenneth C. Schraut Memorial Lecture: One Health: Connecting Humans, Animals and the Environment (Suzanne Lenhart, University of Tennessee) Plenary talk: The Crossings of Art, History, and Mathematics (Jennifer White, St. Vincent College

Performance Enhancement and Characterization of an Electromagnetic Railgun

Collision with orbital debris poses a serious threat to spacecraft and astronauts. Hypervelocity impacts resulting from collisions mean that objects with a mass less than 1g can cause mission-ending damage to spacecraft. A means of shielding spacecraft against collisions is necessary. A means of testing candidate shielding methods for their efficacy in mitigating hypervelocity impacts is therefore also necessary. Cal Poly’s Electromagnetic Railgun was designed with the goal of creating a laboratory system capable of simulating hypervelocity (≥ 3 km/s) impacts. Due to several factors, the system was not previously capable of high-velocity (≥ 1 km/s) tests. A deficient projectile design is revised, and a new design is tested. The new projectile design is demonstrated to enable far greater performance than the previous design, with a muzzle velocity ≥ 1 km/sbeing verified during testing, and an energy conversion efficiency of 2.7%. A method of improving contact and controlling wear at the projectile/rail interface using silver plating and conductive silver paste is validated. A mechanism explaining the problem of internal arcing within the railgun barrel is proposed, and design recommendations are made to eliminate arcing on the basis of the work done during testing. The primary structural members are found to be deficient for their application and a failure analysis of a failed member, loading analysis of the railgun barrel, and design of new structures is undertaken and presented

Non-US electrodynamic launchers research and development

Electrodynamic launcher research and development work of scientists outside the United States is analyzed and assessed by six internationally recognized US experts in the field of electromagnetic and electrothermal launchers. The assessment covers five broad technology areas: (1) Experimental railguns; (2) Railgun theory and design; (3) Induction launchers; (4) Electrothermal guns; (5) Energy storage and power supplies. The overall conclusion is that non-US work on electrodynamic launchers is maturing rapidly after a relatively late start in many countries. No foreign program challenges the US efforts in scope, but it is evident that the United States may be surpassed in some technologies within the next few years. Until recently, published Russian work focused on hypervelocity for research purposes. Within the last two years, large facilities have been described where military-oriented development has been underway since the mid-1980s. Financial support for these large facilities appears to have collapsed, leaving no effective effort to develop practical launchers for military or civilian applications. Electrodynamic launcher research in Europe is making rapid progress by focusing on a single application, tactical launchers for the military. Four major laboratories, in Britain, France, Germany, and the Netherlands, are working on this problem. Though narrower in scope than the US effort, the European work enjoys a continuity of support that has accelerated its progress. The next decade will see the deployment of electrodynamic launcher technology, probably in the form of an electrothermal-chemical upgrade for an existing gun system. The time scale for deployment of electromagnetic launchers is entirely dependent on the level of research-and-development effort. If resources remain limited, the advantage will lie with cooperative efforts that have reasonably stable funding such as the present French-German program

Program: 2021 Undergraduate Mathematics Day

Schedule and general information about the event. 21st Annual Kenneth C. Schraut Memorial Lecture: One Health: Connecting Humans, Animals and the Environment (Suzanne Lenhart, University of Tennessee) Plenary talk: The Crossings of Art, History, and Mathematics (Jennifer White, St. Vincent College

Investigation of flat capacitor discharge electromagnetic launchers

In this thesis, studies of flat or pancake type electromagnetic launcher systems are described. The studies involved the development of several numerical models, and are supported throughout by experimental investigation. The models were based on a coaxial filamentary division technique, and the results they provided were compared with those from a commercial electromagnetic finite element modelling package. They were used to investigate some of the many possible launcher structures and power supply arrangements, as part of a wide-ranging parametric study. The aim of this thesis was to gain an insight into the factors that affect the performance of the launchers. Several different techniques were implemented to reduce the computation time. Practical experimentation provided a clear demonstration of the launcher technology, and supplied valuable model validation data. To aid the experimental work new projectile speed and yaw measurement systems were developed, and these were supported by results from a high-speed camera. A novel dual projectile launcher was tested, and was shown to improve the launch efficiency and to operate at higher energies, due to the reduction in drive coil recoil. Projectile deformation was investigated in both solid discs and flat annular projectiles

Electromechanical Numerical Analysis of an Air-Core Pulsed Alternator via Equivalent Network Formulation

In this paper, the numerical analysis on an air-core pulsed alternator is presented. Since compulsators are characterized by very fast electromechanical transients, their accurate analysis requires strong coupling between the equations governing the electrical and the mechanical behaviors. The device is investigated by using a dedicated numerical code capable to take into account eddy currents, compensating windings, as well as the excitation/control circuits. Furthermore, the code is capable of modeling centrifugal forces and vibrations acting on the shaft due to electric and mechanical unbalances or to misalignments of the shaft from its centered position. This makes the code a very powerful tool during the design phase. Examples of application of the code to machines with nonuniform compensating shield and with shorted compensating windings are shown

Environmental benefits of chemical propulsion

This paper identifies the necessity of chemical propulsion to satellite usage and some of the benefits accrued through monitoring global resources and patterns, including the Global Climate Change Model (GCM). The paper also summarized how the satellite observations are used to affect national and international policies. Chemical propulsion, like all environmentally conscious industries, does provide limited, controlled pollutant sources through its manufacture and usage. However, chemical propulsion is the sole source which enables mankind to launch spacecraft and monitor the Earth. The information provided by remote sensing directly affects national and international policies designed to protect the environment and enhance the overall quality of life on Earth. The resultant of chemical propulsion is the capability to reduce overall pollutant emissions to the benefit of mankind

Investigation on cutting metals using induced currents

textNon-contact magnetic cutting (NCMC) is a recently developed metal-cutting technology that uses pulsed magnetic fields to advance and steer fine cuts in metal sheet. With this process, a coil is used to induce currents in a workpiece that has a starter feature such as a notch or slit. The induced currents are forced to bend tightly around the starter feature, which enhances the current and magnetic field density. Under the right conditions, resistive heating and large J × B forces cause localized melting and ejection of material. Each cut is only a fraction of a millimeter long; however, the process can be repeated and the coil can be moved to cut arbitrary lengths and shapes. While some promising results have been obtained, the operating space for making controlled cuts appears to be narrow. Furthermore, the process by which cutting occurs is not well understood. The objective of this dissertation is to provide the scientific underpinnings of NCMC by experimentally assessing the conditions for controlled cutting, developing a method for predicting conditions for optimal cutting, and identifying a path to reduce NCMC to practice.Electrical and Computer Engineerin