- TITLE:
RELIABILITY ASSESSMENT OF POWER THYRISTORS USED IN POWER SUPPLIES FOR INDUCTION HEATING TECHNOLOGIES
- AUTHOR(S):
Prodan Prodanov, Dobroslav Dankov
- ABSTRACT:
Determining the reliability of power sources for induction technology is a complex task given the
diversity of schemes solutions, technology applications and operating conditions. Trustworthy results
for the dependability of power supplies for induction technologies are obtained by the using of
operational reliability. For its determination has needed to create a database for electrical and
thermal operating by specific environment conditions. Most important parameter is a temperature in
cooling system of the power semiconductors. In this paper is considered reliability of power
semiconductors in dependency of thermal resistance of heat sink and water flow through it. The
results indicate the probability of failure of the power semiconductors in dependency of water flow
through the aluminium or copper heat sink.
- PAGES:
101-
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RELIABILITY ASSESSMENT OF POWER THYRISTORS USED IN POWER SUPPLIES FOR INDUCTION HEATING TECHNOLOGIES
- TITLE:
TEMPERATURE-DEPENDENT CONSTITUTIVE MODEL OF THE SURFACE LAYER OF 2024-T3 ALUMINUM ALLOY SUBJECTED TO SURFACE PLASTIC DEFORMATION
- AUTHOR(S):
V. P. Dunchev, P. P.Peneva
- ABSTRACT:
A temperature-dependent constitutive model of 2024-T3 high-strength aluminum alloy is
proposed, applying the "flow stress" concept. The model defines the relationship between the stress
and strain tensors for a point of the surface layer subjected to surface plastic deformation (SPD).
The model is developed on the basis of combined approach, which includes experimental test
(identification test) and inverse finite element analysis of the experimental test. The developed
constitutive model takes into account the temperature influence on the surface and sub-surface layers
of 2024-T3 high-strength aluminum alloy in the range of T = (50 ÷ 300) ° C . The model can be used
for numerical simulations in order to study the stressed and strained state of components subjected to
SPD and consequent mechanical and/or temperatural loads
- PAGES:
79-
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TEMPERATURE-DEPENDENT CONSTITUTIVE MODEL OF THE SURFACE LAYER OF 2024-T3 ALUMINUM ALLOY SUBJECTED TO SURFACE PLASTIC DEFORMATION
- TITLE:
APPLICATION OF DIFFERENTIAL-MORPHOLOGICAL METHOD FOR DEVELOPING A DEVICE FOR SPD BY MEANS OF TOROIDAL ROLLER
- AUTHOR(S):
T. P. Atanasov
- ABSTRACT:
Toroidal roller burnishing is a cost effective process for finishing of metal machine elements by
means of surface plastic deformation. The surface integrity of the burnished components is
characterized by low roughness, high micro-hardness and beneficial compressive residual stresses.
The deforming tool is toroidal roller made of tool steel. In order to study the burnishing process, a
corresponding device is necessary. This paper is devoted to synthesis and development of
conventional roller burnishing device, allowing easy and quickly set of the geometrical and physical
parameters of the process. For this purpose a morphological analysis of existing burnishing devices
using rolling contact was made. Using the differential-morphological method, a device functional
scheme is justify and chosen. On this basis, a construction of the device is designed and
manufactured. The device is intended for comprehensive experimental study of the toroidal roller
burnishing process
- PAGES:
70-
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APPLICATION OF DIFFERENTIAL-MORPHOLOGICAL METHOD FOR DEVELOPING A DEVICE FOR SPD BY MEANS OF TOROIDAL ROLLER
- TITLE:
SYNTHESIS OF STRUCTURES OF SPINDLE UNITS WITH ELECTROMECHANICAL ACTUATORS OF CLAMPING MECHANISMS AS COMPLEX COMBINED AXISYMMETRIC SYSTEM
- AUTHOR(S):
B. I. Prydalnyi, Y. M. Kuznetsov
- ABSTRACT:
A new approach to creation spindle units with electromechanical drivers of clamping mechanism for
machine tool by using the genetic-morphological approach is proposed. Certain provisions of the
theory of genetic structural-schematic synthesis of spindle units according to objective search
function are highlighted. The motor spindle with an electromechanical clamping mechanism is
considered as a combined system that creates a spatial composition of two structures where each
performs its function. The model of formatting technical units like "motor-spindle" as a complex
combined system with possibility of its description at different levels of structural complexity is
presented. The features of developing new technical system as a process of its evolution with
transferring individual information from one generation to another are taken into account. Based on
new principle, a combination of new and well-known technical solutions in the design of a new
technical object is made. This approach opens up the possibility of formulating fundamentally new
system-level tasks related to the identification principles of structural organization and the laws of
development objects and systems of technological equipment.
- PAGES:
66-
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SYNTHESIS OF STRUCTURES OF SPINDLE UNITS WITH ELECTROMECHANICAL ACTUATORS OF CLAMPING MECHANISMS AS COMPLEX COMBINED AXISYMMETRIC SYSTEM
- TITLE:
INCREASING THE EFFICIENCY OF DIAMOND DRILLING OF CARBON COMPOSITES BY A DEVICE WITH COMBINED ELECTRIC MACHINES
- AUTHOR(S):
O. Salenko, O. Chencheva, V. Shchetynin, V. Gluchova, L. Evgeny, M. Budar
- ABSTRACT:
The paper presents an original solution to the actual problem of increasing the efficiency of the
drilling of composite materials of the carbonic group through the use of coupled electric rotary type
machines whose combination of movements allows to obtain controlled rotary-reciprocating motion
of the instrument. Show, by creating cyclic low frequency load of the cutting zone, it is possible to
improve the efficiency and quality of processing, without destroying the composite. Stress state of the
cutting zone in composite materials based on carbon fibers has been evaluated and it is proved that
their processing with ring diamond-coated drills is reasonable and effective. The use of a cyclic
linear feeder allows significantly reducing the thickness of the destructive layer and reducing the
cutting force, requiring further research on the issue of rational geometric dimensions of the tool
end, the presence of cavity elements on it to remove the microstrip from the processing area.
It is also proven that the proposed design of a power head with coupled electric machines to
provide rotary and translatory motion in coaxial execution is a promising technical solution that can
be successfully implemented in both manual tools and automated processing programmed control
systems.
- PAGES:
52-
- DOWNLOAD:
INCREASING THE EFFICIENCY OF DIAMOND DRILLING OF CARBON COMPOSITES BY A DEVICE WITH COMBINED ELECTRIC MACHINES
