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”.
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”.
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
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”.
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.