¹1 (30), 2008
Synthesis of a five-bar
linkage mechanism with two degrees
of freedom according to the control system of motion of input links. N. Davitashvili, D. Tavkhelidze. “Problems of Mechanics”.
In the article is given the synthesis of a five-bar linkage mechanism with two degrees of freedom according to the control system of predetermined motion of input links. It is shown, that how can be obtained set of coupler curves by means of controlling of input links with invariability length of the lasts. These kind mechanisms can be used for practical purposes. On the basis of equations of trajectories of connective centre of cranks by means of usage of the method of punctual interpolation are calculated. 9 ill. Bibl. 12. Engl.; summ. in Russ.
The synthesis of
lever-differential mechanisms with regular structural elements. V.
Gogilashvili, T. Kakhetelidze, K. Iluridze. “Problems of Mechanics”.
In the paper we consider the kinematic synthesis of lever-differential mechanisms with regular structural elements according to the limit position of links. The analytical dependences for determination of the kinematic parameters of input drive contour are obtained. The conditions providing the solution of the synthesis problem are given. 3 ill. Bibl. 4. Engl.; summ. in Russ.
NEW SPACE REFLEX STRUCTURES. E. Medzmariashvili, Sh. Tserodze, N. Siradze, A. Sarchimelia, N.
Tsignadze, M. Sanikidze. “Problems of Mechanics”.
In the given article we offer a structural analysis of the large deployable reflector and a description of the developed model. Based on the proposed structural configuration, a mathematical model of the reflector deployment process has been developed so as to perform calculations for the stress-strained state of reflector structure elements during deployment. As a result, the time-dependent trajectories and coordinates of all reflector nodes are obtained and thus we can determine forces acting in the elements and to obtain animation. 18 ill. Bibl. 5. Engl.; summ. in Russ.
Development Prospects of
the Rotor Internal Combustion Engines. G.
Bokuchava, R. Turmanidze, M. Beridze. “Problems of Mechanics”.
In this article an attempt is made to give an analysis of the widely used up to now four-stroke internal combustion engines. Despite the fact that these engines for a long time have been continuously updated their efficiency could not overcome a 35% mark. Simultaneously it was impossible to reduce noticeably the pollution level of the environment. In this aspect in our view it seems expedient to concentrate efforts on the development of rotor engines which having definite advantages in this plan. 5 ill. Bibl. 4. Engl.; summ. in Russ.
EFFICIENCY OF GENERATION OF MECHANICAL ENERGY IN THE
NONEQUILIBRIUM SYSTEM AND QUESTIONS OF RECEPTION OF ENERGY FROM ENVIRONMENT. A. Aptsiauri. “Problems of
In work methods of reception of the maximum mechanical energy from natural energy sources are analyzed. It is shown, that the basic obstacle for energy generation in equilibrium system is the problem of recycling of the fulfilled carrier of energy. The attention that the gas stream, in difference from a thermal stream, can take out in environment the energy rests at low temperature is paid. Hence, the scheme of regeneration of thermal energy in mechanical work by use of the interfaced cycles which are carried out in system of two working bodies with identical pressure at different temperature is offered. It is shown, that when limits of change of loop variables are wider than limits of change of parameters of surrounding bodies, it is possible to create a certain class of installations which, at full observance the requirement of the first and second laws, theoretically allows to overcome the limit of efficiency of Karnot. Hence, the methodological basis for creation of new family of thermal installations which allow to receive mechanical energy from environment is put in pawn. 8 ill. Bibl. 5. Engl.; summ. in Russ.
Presented article describes possibilities of calculation of the low speed diesel engine air temperature at the turbocharger outlet (air cooler inlet). Based on marine engines manufacturers publications an empirical equation has been formulated allowing to determine the mentioned above parameter. Measuring session has been carried out during the engine operation under real ambient condition confirming accuracy of worked out equation. 4 ill. Bibl. 9. Engl.; summ. in Russ.
STRUCTURE AND KINEMATIC ANALYSES OF ARCH TRANSFORMED STRUCTURE. E.
Medzmariashvili, V. Gogilashvili, M. Sanikidze, N. Siradze, N. Tsignadze. “Problems of Mechanics”.
In this paper the structural and kinematic analysis of arch transformed system with regular structural elements is considered. Laws of change of geometrical parameters of system which provide disclosing system on an arch surface according to the given initial parameters are defined. 8 ill. Bibl. 6. Engl.; summ. in Russ.
TO A QUESTION OF CONSTRUCTION OF APPROXIMATING
MODELS FOR MECHANICAL SYSTEMS OF DRIVES WITH ELASTIC JOINTS. T. Mchedlishvili, B. Navrozashvili, G.
Goletiani, G. Gratiashvili. “Problems of Mechanics”.
N 1(30), pp. 62 - 66, (Engl.)
In this paper the questions of construction of approximating models for multi-mass systems of drives, complex in the structural sense, are considered. As a result of the conducted investigations the original method of passage to simplified models is offered. Bibl. 7. Engl.; summ. in Russ.
Analysis and Synthesis of
REDUCTION Problem OF TERMINAL CONTROL ThEORY.
One of the most important problems of terminal control - reduction problem is considered and solved. On the base of spinor representation of spatial rotation group, the control law functions are obtained. A mathematical model of reduction process is constructed. The results can be used for practical purposes to elaborate simple control algorithms of spatial movement reduction process in many different fields. Bibl. 3. Engl.; summ. in Russ.
CONDITION OF A BEARING WALL PANEL WITH FACING PLATES BY TAKING INTO ACCOUNT THE
CREEP OF CONTACT SEAM. S. Daveyan. “Problems of Mechanics”.
In the article, the developed theory of calculation of the strength of contact seam of a facing plate and a bearing wall panel with taking into consideration the creep of solution is given. The calculation formulas for determination of normal and tangential forces, used for optimization of the parameters of facing plates, are obtained. 2 ill. Bibl. 3. Engl.; summ. in Russ.
considerations about definition of optimal height of composed, welded beams
according to N. S.
Streletsky. N. Berishvili, Kh.
The study discusses the task of defining the optimal height of composed welded beams given in the works of different prominent authors. The study points out those inaccuracies and inconsistencies that exist despite preliminary estimates and that make it difficult and often impossible to properly use a mathematical method. The study shows how to define the above-mentioned inconsistencies and namely the coefficient , how to define the dependence of on as well as how to avoid them in order to make a correct selection of beams’ heights from the perspective of both mathematical and construction mechanics methods. 1 ill. Bibl. 4. Engl.; summ. in Russ.
The boundary value problem of steady-state oscillation for the
infinite space with spherical cavity in asymmetrical theory. M. Khmiadashvili, K. Skhvitaridze, M. Kharashvili. “Problems of Mechanics”.
The boundary value problem of steady-state oscillation for the infinite space with spherical cavity in asymmetrical theory is solved. The theorem about uniqueness of solution is proved. The solution of the problem is given in the form of absolutely and uniformly convergent series. Bibl. 10. Engl.; summ. in Russ.
DETERMINATION OF DYNAMIC STRESSES IN THE BUCKET
CHAIN OF OPERATING UNIT OF A DREDGER. G.
Tsulaya, L. Sutidze. “Problems
The dynamic scheme of a modernized unit of the tension drum of a multibucket chain of operating member of a dredger is considered. It is given a differential equation and investigated the possibilities of a safety device for equalizing tensions in both branches of pull chain during rotation of a ladle after its encounter with an insurmountable obstacle. 7 ill. Bibl. 6. Engl.; summ. in Russ.
cycle with high compression and internal heat – circulation - a possible way to
new limits of efficiency of thermal energy transformation. A. Aptsiauri. “Problems of Mechanics”.
In work the scheme of regeneration of thermal energy in mechanical work by use of a cycle which is carried out in system of two working bodies with identical pressure and different temperature is offered. It is shown, that use of high, non-stationary compression before contact of working bodies of different temperature theoretically allows to overcome a limit of efficiency of Carnot. The basic conditions which at corresponding assumptions, theoretically assume possibility of full regeneration of heat are formulated. Hence, the methodological basis for creation of new family of thermal installations which allows to come nearer to a theoretical limit of efficiency of transformation of heat as much as possible is put in pawn. 2 ill. Bibl 6. Engl.; summ. in Russ.