Rozprawy doktorskie na temat „Magnetic pulse generator”
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Sofi, Khadija. "Optimisation du générateur d'impulsions magnétiques et adaptation énergétique des machines pour les besoins d'assemblage innovants multi-matériaux". Electronic Thesis or Diss., Amiens, 2021. https://theses.hal.science/tel-03856084.
Pełny tekst źródłaMagnetic pulse generators are being used more and more in multi-material forming and welding applications and produce a precise forming of metal parts. This PhD. thesis aims to calculate, using analytical methods, the magnetic field, the magnetic pressure, and the Lorentz force generated during electromagnetic forming of a metal tube. First, we propose to analyze the generator operation using a massive coil in interaction with a magnetic field shaper. Then, we develop the 3D models of these components using FEM and BEM methods in order to determine the evolution of the current and the temperature distributions. In this research work, we experimentally study the impact of the field shaper on the current pulse and then using a thermal camera we measure the temperature distribution in the massive coil. Afterwards, we calculate analytically the distribution of the magnetic field created around the coil based on the mutual inductance of two circular and coaxial coils. Finally, we develop an analytical and numerical study of a tube crimping by magnetic pulses. The used analytical method is based on the calculation of the self-inductance and the mutual inductance of the coil and the tube in 3D order to determine the Lorentz force and the magnetic pressure applied on the tube
Hanák, Pavel. "Systémy pro generování impulsního magnetického vektorového potenciálu". Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-233564.
Pełny tekst źródłaChazottes-Leconte, Aurélien. "Conception et fabrication d'un dispositif de mise en compression par impulsions électro magnétiques (EMP)". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1082.
Pełny tekst źródłaPenning processes are widely used in industries to apply compressive residual stresses into the most solicited part of mechanical pieces. In that way, the compressive residual stresses limit the priming and the propagation of micro-cracks in the material. This increases significantly the lifespan of the treated mechanical piece under fatigue stresses. These existing peening processes have proved their efficiency and also their limitations and weaknesses. The main recurrent defaults are a shallow depth of treatment, a degradation of the surface condition, a random control of the treatment, a material contamination, etc. These problems have led towards the development of news innovative peening processes which allow better performance avoiding some previous defaults briefly evoked. Among these news processes, the electromagnetic peening process seems especially interesting. This process uses high energy electromagnetic fields to induce Lorentz forces into a metallic piece and thus residual stresses. Actually, there is not much information about this process in the literature and no prototype was ever built. The work of this thesis is dedicated to development and realization of an electromagnetic peening prototype. The first chapter of this thesis adresses the state of the art of major peening processes actually in industrial use. Next, the electromagnetic peening process, or EMP process, is described and the electrical needs are exposed. A second state of the art is made about the technological solutions to respond to the EMP needs. The second chapter is about the conception of the EMP prototype with the electrical structure adopted in the previous chapter. The first step is about the inductor sizing to generate an electromagnetic field sufficient enough for a peening application. Next, the storage system is designed depending on the inductor parameters and finally the closing switch is created considering the electrical parameters used for the EMP process. To validate the previous results, a 3D electromagnetic simulation is done. The prototype assembly is presented in the third chapter and also the first experimental test on the EMP prototype. To begin with, an aluminium alloy with low yield strength is selected to be treated. Two different samples forms are used, a thin one, to realize a similar test to the Almen test and thick one to check the EMP depth of treatment. A 3D multiphysics simulation of these experiments is made and these numeric results are next correlated to the experimental ones. In the fourth chapter, an exploratory study is realized on the effects of the residual stresses on magnetic properties of ferromagnetic material, the mumetal
Веселова, Надія Вікторівна. "Становлення і розвиток харківських наукових шкіл у галузі техніки та електрофізика високих напруг (1930–2010 рр.)". Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/17177.
Pełny tekst źródłaThe thesis for the competition of the academic degree of the candidate of the historical sciences, the speciality 07.00.07 – The history of science and technique. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2015. The thesis is devoted to the complex research of the establishment and the development of Kharkiv scientific schools in the field of the technique and the electrophysics of the high-voltages in 1930's – 2010's. In this work the Kharkiv scientific schools in this field were identified for the first time. They are: the scientific school of the high-voltage accelerators in the UFTI headed by academician of USSR A.K. Walter; the scientific school of the technique of high-voltages in the KhPI, the founder of which was the acacademician of the Academy of Sciences of USSR V. M. Khrushchev; the scientific school of magnetic-pulse treatment of metals in KhPI which was founded by professor I. V. Belii. A holistic scientific-historical analysis of the process of technical solutions in electrophysics and the creation of high-voltage installations in leading scientific centers of Kharkiv is carried out in this work. The importance and uniqueness of the high-voltage installations is shown here. The importance and the uniqueness of the high-voltage structures, the conditions of their creation usage in home industry and science are shown here.
Веселова, Надія Вікторівна. "Становлення і розвиток харківських наукових шкіл у галузі техніки та електрофізика високих напруг (1930–2010 рр.)". Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/17176.
Pełny tekst źródłaThe thesis for the competition of the academic degree of the candidate of the historical sciences, the speciality 07.00.07 – The history of science and technique. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2015. The thesis is devoted to the complex research of the establishment and the development of Kharkiv scientific schools in the field of the technique and the electrophysics of the high-voltages in 1930's – 2010's. In this work the Kharkiv scientific schools in this field were identified for the first time. They are: the scientific school of the high-voltage accelerators in the UFTI headed by academician of USSR A.K. Walter; the scientific school of the technique of high-voltages in the KhPI, the founder of which was the acacademician of the Academy of Sciences of USSR V. M. Khrushchev; the scientific school of magnetic-pulse treatment of metals in KhPI which was founded by professor I. V. Belii. A holistic scientific-historical analysis of the process of technical solutions in electrophysics and the creation of high-voltage installations in leading scientific centers of Kharkiv is carried out in this work. The importance and uniqueness of the high-voltage installations is shown here. The importance and the uniqueness of the high-voltage structures, the conditions of their creation usage in home industry and science are shown here.
Chirla, Razvan Cristian. "Attosecond Pulse Generation and Characterization". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313429461.
Pełny tekst źródłaСалам, Буссі. "Електромагнітно-акустичні перетворювачі для ультразвукового контролю металовиробів". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48184.
Pełny tekst źródłaThesis for a Candidate Degree in Engineering (Doctor of Philosophy), specialty 05.11.13 "Devices and methods of testing and determination of composition of substances" - National Technical University "Kharkiv Polytechnic Institute". The dissertation is devoted to development of new ultrasonic electromagnetic-acoustic transducers with a source of pulsed polarizing magnetic field, methods of sensitive testing and diagnostics of metalware with the use of transducers of this type. Analytical review and analysis of modern means and methods of testing and diagnostics via electromagnetic-acoustic method [1-3] of ferromagnetic and electrically conductive or strictly electrically conductive products under conditions of impact of constant and pulse polarizing magnetic fields taking into account the presence of coherent interferences of different types, technical level of modern electromagnetic circuits, means of their power supply, reception of ultrasonic pulses from metalware and their processing, determination of known advantages and disadvantages, and opportunities of their use in research and development. The direction of the research is defined and justified: development of electromagnetic-acoustic transducer in the form of a simplified single-wind coil model [4] of a source of a magnetic polarizing field with a ferromagnetic core and a high-frequency coil, which is located between the core and the sample; by modeling [5] the distribution of induction of polarizing magnetic field at the end face of the core of the magnetic field source and in the surface layer of both ferromagnetic and non-ferromagnetic metallurgy the features of the location of the high frequency coil of inductance under the magnetic field source are effectively determined for the effective excitation of shear ultrasonic pulses (near the peripheral end of the ferromagnetic core) [6]. The increase in number of winds of magnetization coil in presence of a ferromagnetic core leads to a significant increase in time of transients during the process of powering of a pulsed source of a polarizing magnetic field and during its switching off. As a result, the duration of the power pulse increases to 1 ms or more, which leads to an increase in the force of attraction of EMAP to the ferromagnetic product, additional losses of electricity, deterioration of temperature conditions of the transducer. To reduce the duration of powering pulse of magnetic field it is necessary to reduce the number of winds of the magnetizing coil, but this leads to a decrease in magnetic induction magnitude, even in presence of a ferromagnetic core. As a result of rational choice of the design of the magnetic field source, the flat coil of magnetization must be made with a two-window three-wind and made of high-conductive high-heat-conducting material [7-9]. The core should be placed in the windows of the magnet coil only by the ends. As a result, the action time of the magnetization pulse is reduced to 200 μs, which is sufficient for testing of samples up to 300 mm thick. The high-frequency inductor coil is made of two linear working sections that are located under the windows of the coil [9]. In opposite directions of high-frequency current in these working areas, in-phase powerful pulses of shear ultrasonic waves are excited in the surface layer of the product. The ratio of the excited amplitudes of the shear and longitudinal pulses exceeds 30 dB. That is, the coherent pulses of longitudinal waves in the testing of the moon by the method will practically not affect the results of the diagnosis of ferromagnetic products. Design variants of electromagnetic-acoustic transducers with one-wind [7], two-wind [8] and three-wind magnetization coils [9] of a source of a pulsed polarizing magnetic field are developed. With a single-coil [7], the transients are minimal when the power pulse is winded on. However, it is necessary to excite in the coil a current of several kA, which complicates the temperature conditions of the transducer and power equipment. With a three-coil [9] magnetization, the amplitude of the bottom pulses in relation to the amplitude of the interference exceeds 24 dB, which allows for testing and diagnostics of large variety of samples. When using the charge core [9], the ratio of amplitudes increased to 38 dB, which makes it possible to monitor the echo by the method. The method [10] of ultrasonic electromagnetic - acoustic testing of ferromagnetic products is developed. vectors of intensity with duration of several periods of high filling frequency, n and this excitation of the pulses of the electromagnetic field is performed at a time equal to the time of transients to establish the operating value of the induction of the polarizing magnetic field, and the reception of ultrasonic pulses reflected from the product is performed in the time period tпр, which is determined by the expression T – t1 – t2 – t3 < tпр = t1 + t2 + t3 + 2H/C, where T is the duration of the magnetization pulse; t1 is the time of transients to establish the working value of the induction of a polarizing magnetic field; t2 - time of packet pulse of electromagnetic field; t3 is the time of damping oscillations in the flat high frequency inductor; H is the thickness of the product or the distance in volume of the product to be ultrasound; C is the velocity of propagation of shear ultrasonic waves in the material of the product. It is established [9] that the interferences in the ferromagnetic core caused by the Barkhausen effect and magnetostrictive transformation of electromagnetic energy into ultrasound are practically excluded by production of the core blended, usage of the material of the core plates which has a low coefficient of magnetostrictive conversion, perpendicular core plates orientation in relation to the conductors of the working areas of the flat high-frequency inductor, as well as filling of the gaps between the plates with a high density fluid, such as glycerol. It is shown that the sensitivity of direct EMA transducers with pulse magnetization when powered by a batch high frequency probe pulse generator [11] and when receiving via a low noise amplifier [12] provide detection of flat-bottomed reflectors with a diameter of 3 mm or more, probe frequency of 40 Hz, peak high-frequency current of 120A, shear linearly polarized ultrasonic oscillations of 2.3 MHz, high frequency packet pulse duration 6…7 filling frequency periods, magnetization pulse duration 200 μs, magnetization current density of 600 A / mm2 and at the gap between the EMAP and the product of 0.2 mm [9]. The amplitude of the echo momentum reflected from the flaw in relation to the noise amplitude reaches 20 dB. The EMATs developed are protected with 2 utility model patents.
Салам, Буссі. "Електромагнітно-акустичні перетворювачі для ультразвукового контролю металовиробів". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48181.
Pełny tekst źródłaThesis for a Candidate Degree in Engineering, specialty 05.11.13 – Devices and methods of testing and determination of composition of substances. National Technical University “Kharkiv Polytechnic Institute”, Kharkiv, 2020. A relevant scientific – practical problem on development of new types of EMAP for effective ultrasonic control of metal products is solved in the dissertation. Computer simulation of EMAT magnetic fields distribution in pulse magnetization of ferromagnetic and non-magnetic products is performed. Ways to build transducers with maximum sensitivity are established. The method of excitation of pulsed batch ultrasonic pulses due to the sequential formation of pulsed magnetic and electromagnetic fields is developed. Technical solutions for suppression of coherent interference in the core and in the product have been developed. The geometrical and structural parameters of pulsed magnetic field source were determined, which made it possible to excite powerful in-phase packet pulses of high-frequency shear oscillations in a sample. It is shown that the sensitivity of direct EMA transducers with pulse magnetization provide detection of flat-bottom reflectors with a diameter of 3 mm and more at a probing frequency of 40 Hz, a frequency of shear linearly polarized ultrasonic oscillations of 2.3 MHz, a peak current of high-frequency packet pulses of 120 A, duration of batch high frequency current pulses in 6 periods of filling frequency, magnetization pulse duration of 200 μs, magnetization current of 600 A and at the gap between EMAP and product of 0.2 mm.
Goh, Swee-Eng. "An exploding foil shockwave technique for magnetic flux compression and high-voltage pulse generation". Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/14360.
Pełny tekst źródłaMukherjee, Nandini. "Coherent Resonant Interaction and Harmonic Generation in Atomic Vapors". Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc332243/.
Pełny tekst źródłaZabihi, Sasan. "Flexible high voltage pulsed power supply for plasma applications". Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/48137/1/Sasan_Zabihi_Sheykhrajeh_Thesis.pdf.
Pełny tekst źródłaAppelgren, Patrik. "Experiments with and modelling of explosively driven mangetic flux compression generators". Licentiate thesis, KTH, Rymd- och plasmafysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9638.
Pełny tekst źródłaQC 20101103
Han, Sang-Choll. "Optimization of microwave excited CO2 laser system and generation of pulsed optical discharges in strong magnetic fields". [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966063058.
Pełny tekst źródłaDaněk, Michal. "Simulace toroidních cívek v Ansoft Maxwell 3D". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218197.
Pełny tekst źródłaWisher, Matthew Louis. "MegaGauss : a portable 40T magnetic field generator". Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-3498.
Pełny tekst źródłatext
Wisher, Matthew Louis. "Pulsed magnetic field generation for experiments in high energy density plasmas". Thesis, 2014. http://hdl.handle.net/2152/25985.
Pełny tekst źródłatext
Han, Sang-Choll [Verfasser]. "Optimization of microwave excited CO2 laser system and generation of pulsed optical discharges in strong magnetic fields / vorgelegt von Sang-Choll Han". 2002. http://d-nb.info/966063058/34.
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