4(25)/2006

**SUMMARIES**

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**

THE OSCILLATION BEATINGS
IN MACHINES AND THEIR PREVENTING METHODS.**
R. Adamia, A. Milnikov, T. Natriashvili. **“Problems of Mechanics”. ^{}

It is shown that in the
determined (nonrational) correlations of constructive parameters in the
mechanical systems the oscillation beatings (internal resonance) are arisen
which leads to fatigue destroy in the important links of the machines.
Dimensionless generalized parameter is introduced which is effective criterion
for evalution of arising of internal resonance conditions. Determination of
generalized parameter does not demand solution of differential equations of
mechanical systems movement. The range of generalized parameter’s alternation
is fixed the practical realization of which ensures minimization of amplitude
of elastic oscillations in the mechanical systems. 1 ill. Bibl. 7. Engl.; summ.
in Russ.

Dynamic
analysis of hinged mechanisms of sewing-machines working with a principle of
combination of technological operations. **N. Davitashvili, V.
Abaishvili. **“Problems of Mechanics”.

In this work, due to
offered dynamic and mathematical models of the system, a dynamic investigation
of hinged mechanisms of needle, hook, displacement of sewing materials and
thread tightening of sewing-machines is given. Differential equations of motion
of whole system by taking into account inertial and quasi-elastic coefficients,
brought for practical realization on computer by taking into account cyclic
frequence of the system, are obtained. Some recommendations on choice of
mechanisms of sewing-machines are given. 2 ill. Bibl.
10. Engl.; summ. in Russ.

Workspace Analysis of the Parallel Module of
the VERNE Machine.** ****Daniel
Kanaan, Philippe Wenger, Damien Chablat. **“Problems
of Mechanics”.

The
paper addresses geometric aspects of a spatial three-degree-of-freedom parallel
module, which is the parallel module of a hybrid serial-parallel 5-axis machine
tool. This parallel module consists of a moving platform that is connected to a
fixed base by three non-identical legs. Each leg is made up of one prismatic
and two pairs of spherical joint, which are connected in a way that the
combined effects of the three legs lead to an over-constrained mechanism with
complex motion. This motion is defined as a simultaneous combination of
rotation and translation. A method for computing the complete workspace of the
VERNE parallel module for various tool lengths is presented. An algorithm
describing this method is also introduced. 17 ill. Bibl. 14. Engl.; summ. in
Russ.

ON THE PROBLEM OF
OPTIMIZATION OF TRANSIENT PROCESSES IN MECHANIC SYSTEMS BY THE METHOD OF
INTEGRAL CRITERION.** ****R. Adamia, A. Milnikov, T. Natriashvili. **“Problems of Mechanics”.
^{}

It is shown that for the
purpose of providing the optimal processes in mechanical system it is advisable
to provide simulteniously maximum lowering of amplitude of oscillations and
minimum time of their damping. To achieve this purpose it is introduced
integral criterion of optimization. Criterion of minimalization of the given
integral is shown too. Expediency of solution of the problem is also shown by
the well-known method of integral criterion. The developed method allows to
choose values of elastic and inertia parameters of the system physical
realization of which in transition conditions provides considerable lowering of
amplitude of oscillations and maximum rate of their damping. Bibl. 2. Engl.;
summ. in Russ.

Dynamic
investigation of hinged mechanisms by taking into account wear and clearances
in kinematic pairs.** ****N. Davitashvili, N. Mgebrishvili, G. Sharashenidze, N. Khitarishvili. **“Problems of Mechanics”.

In this paper, on a
basis of the analysis of wear problems it is investigated and calculated wear
in hinged mechanisms caused by friction. Dynamic investigation of a plane
four-link hinged crank-and-rocker mechanism with clearances in two rotational
pairs is given. Differential equations of complementary motion for four forms
of motion are received. Considering plane four-link mechanism is investigated
by taking into account wear in kinematic pairs and clearances. As an example it
is given differential equations of complementary motion of the first form of
motion (contact-contact). The data for realization of received differential
equations with computer are given. 4 ill. Bibl. 25.
Engl.; summ. in Russ.

LEIDEMANN’S
FORMULAS COEFFICIENTS CORRECTION FOR PRESENT REQUIREMENTS OF TECHNOLOGICAL
STATE. **Jaromir Mysłowski.** “Problems of Mechanics”.

LIMITATION OF ENLARGEMENT OF THE EXHAUST GAS BOILER HEAT EXCHANGE AREA. **T.
Tuński. **“Problems of Mechanics”.

The
article exhibits limitations of exhaust gas boilers enlargement due to high
values of exhaust gas flow resistance. 2 ill. Bibl. 5. Engl.; summ. in
Russ.

THE LOW-FREQUENCY ELEQTROMAGNETIC
VIBRATING MACHINE AND PROBLEMS OF VIBROPROTECTION OF AN OPERATOR.** H. Tsulaia, M. Tedoshvili, M. Chelidze. **“Problems of Mechanics”.

In the article we
present the electromagnetic resonant vibrating machine working on half
frequency of a feeding network without application of frequency converter.
According to its amplitude-frequency characteristics the machine comes close to
the characteristics of the machine working in a mode of basic resonance. This
work considers personnel’s vibroprotection problems as well. There are
presented areas of the most dangerous reaction frequencies of human body under
low-frequency vibration influence. 7 ill. Bibl. 3.
Russ.

utilization
of petroleum-based residues on modern marine propulsion plants. **P. Rajewski, O. Klyus. **“Problems of Mechanics”.

Methods of utilization
of petroleum-based residues on board sea-going vessels seems be attractive for
owners. The results of combustion of emulsion made of water-containg
petroleum-based sludge , generated in ship^{,}s engine room feeded in
HFO up to 200cSt have been discussed in
the paper. Enlargement of residual fuels up to 600cSt apply new type of fuel cleaning instalations and further problems with combustion of those
type of sludge. 3 ill. Bibl. 10. Russ.

INFLUENCE
OF THE CHARACTERISTIC OF CONSUMER ON STABILITY WORKING MODE OF THE DIESEL
ENGINE.** A. Muchaidze, Kh. MgebriSvili,
I.
Elisabedashvili. **“Problems of Mechanics”.

The
joint job of the diesel engine with the consumer of its energy is considered in
which twisting moment has periodic non-uniformity property. It is marked, that
the composing harmonics of the moment of the consumer are summarized with
harmonics of the moment of the engine, for what in system the
engine-regulator-user the compelled fluctuations able to break stability of
its working mode are raised. Bibl. 4. Russ.

THE FIRMNESS OF HOLEDEGGING AND PILLER-STICKING BAR-STALKS.
**R. Makharoblidze, Z. Makharoblidze, R.
Khadjomia. **“Problems of Mechanics”.

On the
basis of using
mathemaical methods foreseeing
the deformed mechanical
system and holedigging
and piller-sticking conditions
of planting plants
and sticking pillers , the
holedigging and piller-sticking firm
bar calculating engineering
theory is proposed . 1 ill. Bibl. 2. Russ.

EFFECT APPRAISAL OF
AUTOMOBILE WORK ON GASEOUS FUEL.** O. Gelashvili , I. Chkhetia, Dines Ke. Si. **“Problems of Mechanics”.

It is
theoretically proved an opportunity and expediency of operation of gas-cylinder
automobiles and their work on gas fuel such as the applications of liquefied oil (ALO) and compressed natural gas (CNG). Their efficiency is given. Bibl. 4. Russ.

BENCH TESTS OF SERVICEABILITY OF POWER SUPPLY SYSTEM
GAS-DIESEL.** ****O. Gelashvili, N.
Butkhuzi. **“Problems of Mechanics”.

In work
it is investigated serviceability of the power supply system gas-diesel, by
bench tests. It is received, that the skilled power supply system alongside
with reliable work gas-diesel provides improvement of its technical and
economic parameters and prove efficiency of translation of automobiles on gas-diesel
process. 2 ill. Bibl. 4. Russ.

NEW APPROACH TO THE ESTIMATION
OF CONSTRUCTION STRENGTH.** M. Tsikarishvili, K. Babilodze. **“Problems of
Mechanics”.

The article presents the
complex of hardware-controlled computer-aided diagnosis of construction
strength which gives the inference on continuation or discontinuation of
construction operation. The carried out numerical tests have defined three
risk-levels: I – when the principal stress σ_{1,2,3 }in the
element is equaled to elasticity limit σ_{elas.}; II – when the
principal stress σ_{i }in the element is equaled to yield limit
σ_{yield} and III- when the principal stress σ_{i} in
the element is equaled to strength level σ_{str.}. Level I is a
warning level, level II is preaccident situation and level III is the beginning
of accident. 2 ill. Bibl. 2. Russ.

THE GHANGE OF THE IMPACT
FORCE OF CARRIAGE WHEEL PAIR TAKING INTO ACCOUNT VIBRATION OF THE JOURNAL BOX
ROLLING BEARING.** Th. Chkhaidze, N. Chkhaidze, K. Sadagachvili, E. Sadagashvili. **“Problems
of Mechanics”.

Impact loads from rail
joints and defect of the rail track on the non-cushioning parts of the carriage
are considered. The analytical expressions for exact determination of the
impact load subject to vibration level
depending on accuracy class of the learning are suggested. 3 ill. Bibl. 5. Russ.

CONSTRAINEDLY-WARPING CONDITION OF DIAPHRAGM WITH EMBRASURE INFLUENCE
UPON LOAD AFLAT.** S. ****Daveyan. **“Problems of Mechanics”.

A theory of
calculation for dangerous cuttings of diaphragm with ebrasures of large
panelling buildings is considered in the article on the basis of
experimental-theoretical investigations. An equalization of tension is offered
arising in transitional plots of diaphragm, which are recommended to practise
upon the calculation on stages of their project. 2 ill. Bibl. 5. Russ.

The FaCILITIES increasing intensification of mixing.
**R.
Varsimashvili, M. Kakhiani, N.
Khveliashvili****. **“Problems
of Mechanics”.

The schemes of mixing and kneading facilities, assuring the increase of mixing intensifications of different products by the usage of planetary gearbox with noncircular wheels, are discussed. 4 ill. Bibl. 3. Russ.