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Article
Publication date: 1 March 2005

Jerzy Barglik, Ivo Doležel, Pavel Karban and Bohuš Ulrych

As far as the authors know, no sufficiently complete model of continual induction hardening was developed and solved so far. The paper presents both mathematical model of…

Abstract

Purpose

As far as the authors know, no sufficiently complete model of continual induction hardening was developed and solved so far. The paper presents both mathematical model of the process and algorithm of its solution in the quasi‐coupled formulation.

Design/methodology/approach

Computation of electromagnetic and temperature fields is based on the finite element method, while time variable boundary conditions are determined by means of an original theoretically‐empirical procedure.

Findings

Substantial are backgrounds for design of the inductor and parameters of the field current as well as parameters of the cooling medium.

Research/limitations/implications

The model reached a good level of accuracy validated by suitable experiments. Nevertheless, next work in the field will also have to respect history of the heating before cooling itself (the austenitizing temperature is a function of the velocity of heating). Very important is also appropriate meshing of the investigated region to suppress numerical instabilities appearing during the computation process. Finally, acceleration of numerical schemes is a must, because modelling of one common task (on very fast PCs) takes about 4 h.

Practical implications

The results and conclusions may be used for designing devices for continual induction hardening of axisymmetric bodies.

Originality/value

Complete mathematical and computer model of the process, original methodology for finding the coefficient of convective heat transfer from the cooled part of the heated workpiece to ambient water spray.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 1 September 2004

Ivo Doležel, Ladislav Musil and Bohuš Ulrych

Impedance of long direct massive conductors carrying time‐variable currents is a complex function of time. Its evolution is affected not only by the skin effect but also…

Abstract

Impedance of long direct massive conductors carrying time‐variable currents is a complex function of time. Its evolution is affected not only by the skin effect but also by the temperature rise. This paper presents a numerical method that allows one to compute the resistance and internal inductance of a non‐ferromagnetic conductor of any cross‐section from values of the total Joule losses and magnetic energy within the conductor, and also illustrates the theoretical analysis based on the field approach on a typical example and discusses the results.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 14 August 2007

Ivo Doležel, Pavel Karban, Bohuš Ulrych, Mykhailo Pantelyat, Yuriy Matyukhin and Pavlo Gontarowskiy

The purpose of this paper is to investigate the parameters and operation characteristics of an actuator working on the principle of thermoelasticity whose structure was…

Abstract

Purpose

The purpose of this paper is to investigate the parameters and operation characteristics of an actuator working on the principle of thermoelasticity whose structure was designed by the authors.

Design/methodology/approach

The mathematical model of the system describes the effects of three physical fields (electromagnetic field, temperature field, and field of mechanical strains and stresses due to thermoelasticity). While the electromagnetic field was solved independently, the thermomechanical task in common with the contact problem was solved in the hard‐coupled formulation. The computations were mostly carried out by own codes.

Findings

This type of actuator is characterized by extremely high forces acting in its dilatation element.

Research limitations/implications

The parameters of the system may still be improved using a longer field coil and dilatation element. Attention has to be paid, however to the mechanical stability of the system. Another improvement could be achieved by suitably designed cooling of the coil that would allow increasing parameters of the field current (its frequency or amplitude).

Practical implications

The device is promising for various fixing tasks in the industrial environment.

Originality/value

Although the methods of numerical processing of particular fields are known, the paper provides an algorithm for their simultaneous solution while respecting the temperature dependencies of the material properties and continuous change of the contact surfaces.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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