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1 – 4 of 4M. Pantelyat, M. Shulzhenko, Y. Matyukhin, P. Gontarowskiy, I. Dolezel and B. Ulrych
The paper seeks to present a methodology of computer simulation of coupled magneto‐thermo‐mechanical processes in various electrical engineering devices. The methodology allows…
Abstract
Purpose
The paper seeks to present a methodology of computer simulation of coupled magneto‐thermo‐mechanical processes in various electrical engineering devices. The methodology allows determining their parameters, characteristics and behaviour in various operation regimes.
Design/methodology/approach
The mathematical model consisting of three equations describing magnetic field, temperature field and field of mechanical strains and stresses (or thermoelastic displacements) is solved numerically, partially in the hard‐coupled formulation.
Findings
The methodology seems to be sufficiently robust, reliable and applicable to a wide spectrum of devices.
Research limitations/implications
At this stage of research, the hard‐coupled formulation of thermo‐mechanical (or thermoelastic) problems is still possible only in 2D.
Practical implications
The methodology can successfully be used for design of numerous machines, apparatus and devices from the area of low‐frequency electrical engineering ranging from small actuators to large synchronous generators.
Originality/value
Complete numerical analysis of coupled magneto‐thermo‐mechanical phenomena in electrical devices.
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Keywords
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 designed…
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
Keywords
I. Doležel, V. Kotlan, E. Krónerová and B. Ulrych
The purpose of this paper is to present a new device (thermoelastic actuator) for accurate control of position whose principle is based on thermal dilatation of its working unit…
Abstract
Purpose
The purpose of this paper is to present a new device (thermoelastic actuator) for accurate control of position whose principle is based on thermal dilatation of its working unit brought about by induction heating.
Design/methodology/approach
The device must satisfy the prescribed operation parameters (mainly the above thermal dilatation). The task to find them is a multiply coupled problem (interaction of electromagnetic field, temperature field and field of thermoelastic displacements) that is solved by the finite element method supplemented with a number of other procedures.
Findings
The control of position based on the described thermoelastic effect is very accurate and ranges from 1×10−6 to 1×10−3 m.
Research limitations/implications
The device also contains two self‐locking friction clutches of conical shapes whose purpose is to fix the position of the plunger in the prescribed position. Further attention should be paid to their dynamic behaviour during the process of fixing.
Practical implications
The device can be used in various technical domains such as optics and laser or microscope techniques.
Originality/value
The principal part of the device contains no movable element, which is a substantial advantage in comparison to other systems based on mechanical, hydraulic or pneumatic principles working with movable elements or media.
Details
Keywords
The purpose of this paper is to question the periodization of Russian political and economic development that sees a break occurring between the Yeltsin and Putin presidencies. It…
Abstract
Purpose
The purpose of this paper is to question the periodization of Russian political and economic development that sees a break occurring between the Yeltsin and Putin presidencies. It does this by looking at how political problems common to late developing nations influenced the development of reform programs in Russia under its first two presidents.
Design/methodology/approach
The paper applies concepts from the literature on development to Russia, using it as a case study to develop an alternative historical narrative on Russian political economy.
Findings
The paper finds that there was more continuity in political conditions between Yeltsin and Putin and that economic change in Russia under Putin was not achieved because a political consensus over economic policy developed but because the wealth generated by hydrocarbon exports enabled Putin to buy support. Whilst this has meant that there was less contest over economic policy during the Putin presidency, it is far from certain whether this means of managing the economy can last over the longer term if the price of oil declines.
Originality/value
The paper demonstrates the need for political reform in Russia as a condition of economic change, something that is beginning to be taken seriously in Russian political circles after the experience of economic crisis that followed Putin.
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