#4(49), 2012
SUMMARIES
kinematics
research of seven-bar Automatic manipulator by analytical method. N. Davitashvili. “Problems of Mechanics”.
Tbilisi, 2012, ¹ 4(49), pp. 5-10, (Engl.).
In stated the description of principle of operation and
kinematical research by analytical method of seven-bar spherical automatic
manipulator that is created on the basis of spherical four-bar slider-crank
mechanism. The kinematical parameters - positions, linear and angular
velocities and accelerations of links and their points of automatic manipulator
are defined in the function of generalized coordinates and time. Results of
research are available for synthesis of mentioned mechanism. The preconditions for
dynamical analysis of manipulator are revealed. 2 ill. Bibl. 11. Engl.;
sum. in Russian.
A
contribution to the description of the mechanical behaviour of veneer using a
linear-elastic orthotropic material model. Bernd
Bellair, Andreas Dietzel, Martin Zimmermann, Hendrike Raßbach, Klaus
Zimmermann. “Problems of Mechanics”. Tbilisi,
2012, ¹ 4(49), pp. 11-21, (Engl.).
The product
development process as well as the production of laminated veneer lumber used
for chairs and design objects is traditionally based on the experience of the
staff. Such an experience based approach for developing forming tools and
manufacturing sample parts requires an iterative process. Sample parts are
checked for cracks and other optical defects (in-plane contraction) and changes
to the 3D-design are made in collaboration with the designers. These iterations
are essential until a high quality product is the result. In order to save time
and money in the product development process, the feasibility of an initial
3D-design should be checked by means of simulation.
This article
presents a methodology for the identification of material parameters on red
beech veneer and the use of these characteristics in material models and
failure criteria. The objective is to create the basis for the description of
the mechanical behaviour of veneer under different climatic conditions, in
order to simulate the 3D-forming process of laminated veneer lumber. Initially,
the specific properties of veneer and the continuum mechanical principles are
presented. Based on this, an appropriate experimental methodology and data
processing is introduced. The results of the experiments are discussed and
compared with simulation results. 9 ill. Bibl. 21. Engl.; sum. in Russian.
Constructive logic of
created by double pantograph deployable load-bearing ring reflector. E. Medzmariashvili. “Problems of Mechanics”. Tbilisi, 2012, ¹ 4(49), pp.
22-36, (Engl.).
In the
article, proceeding form construction principles and the theory of
transformable systems is studied and developed the generalized model of
reflector with deployable. It has the center composed of two mutually opposite
concaved mesh.
33 ill. Bibl. 3. Engl.; sum. in Russian.
dynamical
research of cone crusher drive mechanism by computing machinery. A. Talakvadze. “Problems of Mechanics”. Tbilisi,
2012, ¹ 4(49), pp. 37-47, (Engl.).
Is stated the dynamical research of cone crusher
drive mechanism by computing machinery. As crusher drive is presented spherical
crank-slider mechanism with clearances in two kinematical pairs, dynamical
analysis of that is realized by taking into account the additional and basic
motions of mechanism. Due the
comparative analysis of obtained results is revealed the possibility of
selection of optimal clearances in kinematical pairs, stipulating the normal
and reliably operation of crusher drive. 8 ill.
Bibl. 8. Engl.; sum. in Russian.
new method of transformation heat in compressor
of cascade exchange by pressure. Aleksander Krajniuk, Oleh Klyus. “Problems of Mechanics”. Tbilisi, 2012, ¹ 4(49), pp.
48-52, (Engl.).
A
new method of organization of working cycle of device of direct transformation
of heat in the located work of compression of air, based on principle of
cascade exchange by pressure, is exposed; the results of pre-selection of basic
dimensional and structural parameters of
thermal compressor of cascade exchange by pressure are adduced; some special
features of its working process are considered; main directions of perfection of working cycle of
thermal compressors of cascade exchange of pressure are shown. 4 ill. Bibl. 3. Engl.;
sum. in Russian.
Transformation of heat into useful work in rotary
fluid converter, as consequence of energy equation conflict with angular
momentum conservation law. A.
Aptsiauri. “Problems of Mechanics”. Tbilisi, 2012, ¹ 4(49), pp. 53-58, (Engl.).
In the article is stated with taking
into account in the field of alternative energetics, is given a positive answer
on the issue of useful work generation from environmental heat. Is shown that
such a possibility, in particular, appears in such rotary installations in
which is observed the evident conflict between the fundamental laws. The scheme
of such installation is presented. 1 ill. Bibl. 10. Engl.; sum. in
Russian.
calculation of City routes fuel consumption
according to bus traffic conditions. O. Gelashvili, P. Bezhanishvili. “Problems of Mechanics”. Tbilisi, 2012, ¹
4(49), pp. 59-62, (Engl.).
Are considered on city bus routes traffic conditions and fuel
consumption calculation method according to the phases. At bus operation in
urban conditions is proposed a new approach for determining the fuel
consumption, that takes into account the engine structures and modes of
operation. The original method has been developed that would be a basis for
determining the fuel route consumption norms for bus operation in urban
conditions. 2 ill. Bibl. 6. Engl.; sum. in
Russian.
CONICAL REFLECTOR DEPLOYABLE RING STRUCTURE WITH V-FOLD BAR’S. Sh. Tserodze, E. Medzmariashvili, N. Tsignadze, O. Tusishvili, J. Santiago-Prowald. “Problems of Mechanics”. Tbilisi,
2012, ¹4(49), pp. 63-70, (Engl.).
In the article
is considered the structural analysis of reflector that’s unfolding ring is
conical and central part is the net mesh. The ring supports are connected with
V-fold bars. Here are given the structure of central joints connecting V-fold
bars and the structure of joints connecting V-fold bars with posts. On all
posts the V-fold bar’s deployment synchronization are arranged in joints of
rods deployment synchronization, what with its determination is the novelty.
The mentioned joint has ability of rotation towards its axis, which is the main
condition for the deployment of conical ring. Stabilization and control of
system deployment is carried out through the cables and driving devices. On
flexible center the front and rear net meshes are connected with beams in
parallel arrangement. 10 ill. Bibl. 3. Engl.; sum. in Russian.
THEORETICAL AND EXPERIMENTAL STUDY OF REFLECTOR ANTENNA. G. Bedukadze,
E.
Medzmariashvili, K. Chkhikvadze, M. Sanikidze. “Problems of Mechanics”.
Tbilisi, 2012, ¹ 4(49 ), pp. 71-83, (Engl.).
Paper discusses the
results of theoretical calculations of reflector with 4 meter aperture and its
experimental researches. Experimental researches including the static and
dynamic influences on reflector, study of its stability and determination of
eigen frequencies. The results of surface accuracy and the shape repetition
during the multiple deployments are given in experiment. 15 ill. Bibl. 8. Engl.; sum. in Russian.
Dynamics of machine-tractor unit
with variable mass. R. Makharoblidze, I.
Lagvilava, O. Asatiani, Yu. Dzirkvadze, A. Kobakhidze. “Problems of Mechanics”. Tbilisi,
2012, ¹ 4(49), pp. 84-88, (Engl.).
Is studied the dynamics of transition processes in the
machine-tractor units with variable mass at real change disconnect
or joining masses that is most often used in the function of movement
on analysis of dynamics of aerial
ropeway drive system. T. Mchedlishvili, D.
Balakhadze, K. Demetrashvili, G. Nadirashvili, I. Elerdashvili. “Problems of Mechanics”.
Tbilisi, 2012, ¹ 4(49), pp. 89-92, (Engl.).
To drive systems of aerial
ropeways cars are raised increased requirements due points of technical
performances view that in turn is largely depended on the effectiveness of used
at their calculations mathematical models of dynamics. Due the latter would be
determined kinematic and structural parameters of systems. In this article are
considered the issues of mathematical models construction by that is possible
the further improvement in the efficiency of computational researches. Bibl. 6. Engl.; sum. in Russian.
Effect of heat treatment on structure of low-silicon
aluminum cast irons. N. Khidasheli, G. Beradze, G. Khvichia. “Problems of
Mechanics”. Tbilisi, 2012, ¹ 4 (49), pp. 93-97, (Engl.).
In the present work are researched the processes
of austenitizing and austenite dissociation in low-silicon aluminum cast irons.
Are defined the time-temperature parameters of bainite and martensite
structures in the mentioned alloys. The active effect of aluminum on phase
composition of cast iron after the heat treatment is shown. 6 ill. Bibl. 11. Engl.; sum. in Russian.
STRAIN CONTINUITY
EQUATIONS IN CASE OF A PLANE PROBLEM IN STRESSES. N. Berishvili, N. Tsignadze, N. Medzmariashvili. “Problems of Mechanics”.
Tbilisi, 2012, ¹ 4(49), pp. 98-100, (Engl.).
In the theory of
elasticity, only a single equation that expresses relation between longitudinal
relative strains and angular strains remains from the system of strain
continuity equations in case of a plane problem, i.e. where the influence of
the third coordinate can be neglected. In the classical elasticity theory,
Hooke’s generalized law is used for expressing the continuity equations by
stresses. Therefore, the stresses appearing in the continuity equations are
partial stresses, upon which influence of normally directed loads are not
reflected. In the present work, strains are expressed by so called full
stresses, envisioning influence of the above mentioned loads. While the thus
obtained Morris Levi condition is similar as to form, the stresses included
therein have different physical essence whatsoever. Bibl.
4. Engl.; sum. in Russian.
PROPERTY OF
It is known from the
classical theory of elasticity that functions expressing the first invariant of