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.
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
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.
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.
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.
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.
OF THE CHARACTERISTIC OF CONSUMER ON STABILITY WORKING MODE OF THE DIESEL
ENGINE. A. Muchaidze, Kh. MgebriSvili,
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
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 σ1,2,3 in the element is equaled to elasticity limit σelas.; II – when the principal stress σi in the element is equaled to yield limit σyield and III- when the principal stress σi in the element is equaled to strength level σstr.. 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
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.
Varsimashvili, M. Kakhiani, N.
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.