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Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 36
Kotlan, Václav , Hamar, Roman , Smolyanov, Ivan Alexandrovich , Doležel, Ivo
Induction-assisted laser welding taking into account phase changes

Purpose – The paper aims to describe the modeling of the induction-assisted laser welding process taking into account the keyhole effect and phase changes in the material. Design/methodology/approach – A sophisticated mathematical model of the above heat treatment process is presented,&...

Pavlíček, Karel , Kotlan, Václav , Doležel, Ivo
Applicability and comparison of surrogate techniques for modeling of selected heating problems

Possibilities of using surrogate techniques for modeling selected strongly nonlinear coupled problems of heating are evaluated. The main purpose is to significantly reduce the computing time in the case of computations of many variants of a given task by the finite element method o...

Štork, Milan , Mayer, Daniel
Modified Tellegen Principle Used for Power and Energy Systems Modeling

The paper deals with a problem of modeling of dynamic systems. The proposed approach to the problem solution is based on modified Tellegen’s theorem well known from electrical engineering. The novelty of this approach is that it is based on the instantaneous power calculation ...

Štork, Milan , Mayer, Daniel
RLC Ladder Oscillators Controlled by Energy Approach

The following topics are dealt with: artificial satellites; CMOS integrated circuits; switching convertors; reliability; DC-DC power convertors; failure analysis; oscillators; capacitors; solar power satellites; network topology.

Štork, Milan , Mayer, Daniel , Hrušák, Josef
Generalized tellegen principle used for energy method for systems modeling

This paper deals with dissipativity, stability, chaotic behavior and related structural properties of a relatively broad class of finite dimensional strictly causal systems. The class of nonlinear systems under consideration is described in the state-space representation form. System properties are&#x...

Pánek, David , Karban, Pavel , Doležel, Ivo
Calibration of numerical model of magnetic induction brazing

A method of finding the temperature dependences of physical parameters of metals is proposed and discussed. The method is based on the combination of measurement of the surface temperature of the material and subsequent solution of the inverse problem using the multi-parametric optimiza...

Štork, Milan , Mayer, Daniel
Direct currents in power transformers

The article is devoted to the physical nature of geomagnetism, magnetic storms and methods of predicting their origin and deals with geomagnetic induced currents called GIC (Geomagnetically Induced Currents) and their effect on power transformers. A simplified, single-phase transmission system is...

Kotlan, Václav , Hamar, Roman , Pánek, David , Doležel, Ivo
Model of depositing layer on cylindrical surface produced by induction-assisted laser cladding process

A model of hybrid cladding on a cylindrical surface is built and numerically solved. Heating of both substrate and the powder material to be deposited on its surface is realized by laser beam and preheating inductor. The task represents a hard-coupled electromagnetic-thermal problem...

Behúň, Lukáš , Slobodník, Karel
Harmonic and pulsed eddy current testing methods as tools for surface and subsurface defect evaluation

In most publications eddy current testing (ECT) methods are said to be suitable for surface defects up to several millimeters. This paper aims to evaluate the detection capabilities of eddy current testing based on two examples of modern approach. One of them is a harmonic...

Doležel, Ivo , Kotlan, Václav , Hamar, Roman , Pánek, David
Numerical solution of electroheat problems with time-varying geometries

Novel approach to modeling of 3D coupled electroheat problems with time-varying geometries is presented. Instead of time-expensive remeshing of the whole system in every time step it is used the initial mesh that takes into account the expected geometric changes. In the course of&#...

Nikolayev, Denys , Zhadobov, Maxim , Karban, Pavel , Sauleau, Ronan
Electromagnetic radiation efficiency of body-implanted devices

Autonomous wireless body-implanted devices for biotelemetry, telemedicine, and neural interfacing constitute an emerging technology providing powerful capabilities for medicine and clinical research. We study the through-tissue electromagnetic propagation mechanisms, derive the optimal frequency range, and obtain th...

Karban, Pavel , Pánek, David , Doležel, Ivo
Model of induction brazing of nonmagnetic metals using model order reduction approach

Purpose: A novel technique for control of complex physical processes based on the solution of their sufficiently accurate models is presented. The technique works with the model order reduction (MOR), which significantly accelerates the solution at a still acceptable uncertainty. Its advanta...

Kotlan, Václav , Hamar, Roman , Šroubová, Lenka , Doležel, Ivo
Hybrid realization of fillet weld

Purpose: A model of hybrid fillet welding is built and solved. No additional material (welding rod, etc.) is used. Heating of the welded parts is realized by laser beam with induction preheating and/or postheating. The purpose of these operations is to reduce the temperature&#...

Hamar, Roman , Kropík, Petr , Šroubová, Lenka
Induced losses in linear equipment buried near an overhead power line

This work focused on the influence of an overhead power line on buried linear equipment (cable, pipeline). Its aim was to analyze the volumetric losses in buried linear equipment as a function of the distance from an overhead power line. The computations were performed numeric...

Benešová, Zdeňka , Kropík, Petr , Šroubová, Lenka , Štekl, Pavel
E-learning: our experience

Preuss, Petr
Duality and infinity in theory of electrical engineering

Mayer, Daniel , Kropík, Petr
Contribution to the minimization of looses in three-phase line

Benešová, Zdeňka
Algorithm for computational of inductances of three-phase overhead lines

Benešová, Zdeňka , Šroubová, Lenka
Reduction of electric and magnetic field of double-circuit overhead lines

Shulzhenko, Mykola , Gontarowskiy, Pavlo , Matyukhin, Yuriy , Pantelyat, Michael , Doležel, Ivo , Ulrych, Bohuš
Numerical analysis of induction heating-based assembly and disassembly fo shrink fits

Collection's Items (Sorted by Submit Date in Descending order): 1 to 20 of 36