SUMMARIES
¹ 3(40)2010
Research OF MANIPULATORs, created by SPATIAL five-bar
mechanism with two degrees of freedom. N.
Davitashvili. “Problems of Mechanics”.
Is
stated study of manipulators, formed by spatial five-bar mechanism with two
degrees of freedom. For the first time are identified 16 different types of
spatial five-bar mechanism of manipulators with taking into account the
combinations of rotational, spherical, cylindrical, and spherical with finger
and prismatic kinematical pairs. The design of spatial five-RSSRR type
manipulator with two degrees of freedom for a given law of motion of robot
output point (gripper) is carried out. 9 ill. Bibl. 10. Engl.; sum. in Russian.
PROBLEM
OF DYNAMIC AND KINEMATIC precision OF passenger carriages optimal brake
leverage with clearances. G. Sharashenidze, M. akhalbedashvili, P.
Kurtanidze, T. Dundua, L. Balon. “Problems of Mechanics”.
According
the developed real dynamic model, for purpose of definition of reaction and
friction forces in the joint connections with clearances are considered the
equilibrium state of each lever and rod with the view of the impact forces. the values of real dynamic loads are
depended on the parameters of generalized coordinates are shown. The analytical
expressions for the friction and reaction forces, as well as for the inertial
forces and moments of inertia with taking into account the braking force of
brake cylinder and the pressing forces of brake shoe on the rolling surface of
railcars wheel are obtained. 2 ill. Bibl. 14. Engl.; sum. in Russian.
A SINGLE-SPAN
DUAL TRANSFORMATION DEPLOYABLE
BRIDGE. E. Medzmariashvili, M.
Sanikidze, V. Gogilashvili, N. Tsignadze, L. Filipenko, G. Medzmariashvili. “Problems of
Mechanics”.
The
work overviews research of various types of designs and new systems of
construction during spatial transformation for the purposes of choosing the
optimal embodiment of the reusable single-span transformable bridge intended
for use in extremal circumstances. Transportation and folding/deployment of the
bridge over an obstacle are performed by means of a single vehicular and
mounting means – tank, motorcar or helicopter. Assembling and dismantling of
the bridge require a few minutes and do not require from the driver or operator
to leave the vehicular and mounting means. The length of its span in the
proposed design is increased up to 48 meters. The folded transport package
weight and dimensions are the same of those of existing 24 meters span bridges.
Based on the conducted researches, an optimal design of the single-span
transformable bridge with corresponding technical characteristics has been
elaborated. 6 ill. Bibl. 4. Engl.; sum. in Russian.
INVESTIGATION OF THE FUNCTIONING OF UNITS OF THE ROTORS WITH VARIABLE
GEOMETRY PARAMETERS. R.S. Turmanidze,
O.G. Rukhadze, E.O.
Rukhadze. “Problems of
Mechanics”.
In the article is carried out a short
review of state of the issue to creation of the airplanes with vertical takeoff
and landing (VTOL). On the basis of scientific-research and experimental
designing works is created a special equipment for investigation of the rotors
with variable geometry parameters (
Calculation of orthotropic two-layered constant and
variable thickness plates by method of initial parameters. Part 1. Calculation
of orthotropic two-layered constant thickness plates by method of initial parameters. G. Bichiashvili, J. Bichiashvili, Z. Bichiashvili. “Problems of
Mechanics”.
In
article is carried out the calculation of round orthotropic single-layered
plate rigidly fixed on the contour, non-located on the elastic (free) variable
thickness foundation with radius a=100 cm and loaded by uniformly distributed
vertical loading of intensity of load q=104 Pa perpendicular of it’s
median surface. Calculation is carried out by the offered method [1,4] on the
basis of method of initial parameters. The number of sites Ê=400 and
radius of the internal rigid site of plate r0=0.25 cm. are constructed the stresses
distribution 
and 
for various points of plate’s cross-section.
Mechanical properties of layers materials are different. 4 ill. Bibl.
5. Engl.; sum. in Russian.
Calculation of orthotropic two-layered constant and
variable thickness plates by method of initial parameters. Part 2. Calculation
of orthotropic two-layered Variable thickness plates by method of initial parameters. G. Bichiashvili, J. Bichiashvili, Z.
Bichiashvili. “Problems
of Mechanics”.
In article is carried out the calculation of round orthotropic two-layer
plate rigidly fixed on edge, with variable thickness layers, non-located on the
elastic (free) foundation with radius a=100 cm and loaded by uniformly
distributed vertical loading, intensity q=104 Pa of perpendicular it
surfaces. Calculation is executed by an offered method [1, 4] on the basis of a
method of initial parameters. The number of sites K=400 and radius of an
internal rigid site of a plate r0 =0,25 cm. Are constructed diagrams
of factors Q, Mr, Mt, W, σr σt,
for various points of cross-section section of plate. Mechanical
characteristics of materials of layers identical, but oriented in different. At
the considered plate the relation 
for different layers are various, due this
longitudinal forces Nr and Nt at bending by loading q are
not equal zero. 3 ill. Bibl. 6. Engl.; sum. in Russian.
THE T-S DIAGRAM AND FRICTION. FALLING OF ENTROPY
AT ACCELERATION OF GAS IN CHANNELS. A. Aptsiauri. “Problems of Mechanics”.
In article, on the basis of
laws of energy and a pulse conservation
is shown, that at acceleration of
thermo isolated stream in real
conditions in spite of the fact that, as a result of friction, total value of
entropy grows, on an initial site of acceleration it should decrease, that
contradicts with the requirement of the second law. The principle of
construction of 
diagrams in
view of presence of dissipation is offered. 9 ill. Bibl. 5. Engl.; sum. in
Russian.
IMPACT
OF ASSEMBLING AN ADAPTED SELF-PROPELLED CHASSIS ON
The article considers the
methods to define
the normal reaction
for the wheels of adapted
self-propelled chassis in
case of balance suspension of the driving tandem
wheels. The calculation formulae for the
normal reactions for the
front guides and driving wheels
are deduced. It is established that the summary normal reaction on the truck is distributed equally between the rear
and front tandem wheels what will
have its impact
on the traction characteristics
of the running system. The normal reactions for
the wheels are determined by considering the assembly of the operating
equipment what allows identifying
the optimal locations of
the technological working
organs along the girders of the chassis by considering the
minimization of the pressure of the
wheels on the soil. 2 ill. Bibl. 5. Engl.; sum. in Russian.
Study of the automobile braking dynamics in the case
of braking by the high-effective motor
brake. B. Kordzadze,
T. Natriashvili, R. Demetrashvili. “Problems of Mechanics”.
The
accomplished work confirms that for comparison of braking properties of
two automobiles it is expedient to
introduce by analogy of the automobile dynamic factor, the automobile braking
factor, with the help of which it will be possible to determine theoretically
such important braking parameters as braking path and braking time are. 7 ill.
Bibl. 2. Engl.; sum. in Russian.
TO THE THEORY OF TEA LEAF TWISTING PROCESS: THE DEGREE OF THE TEA MASS
TWISTING. A. Tvalchrelidze, B. Kankadze.
“Problems of Mechanics”.
Rheological model of the tea mass must underlie theoretical researches
of the tea leaf twisting process - one of the main technological processes in
the BaiHua tea manufacturing. One of the state parameters of tea mass in this
process is a degree of twisting. There is considered in a given article one of
the options for introduction of such parameter. Bibl. 1. Engl.; sum. in
Russian.
On issue of development of plate’s design procedure on axisymmetric
fluctuations. Z. Bichiashvili,
J. Bichiashvili, G. Bichiashvili. “Problems of Mechanics”.
In
article is proved that formulas for definition of natural resonant frequency of
circular and ring, as well as square plates are not represented as exact that
is caused by various values of Poisson's ratio for different materials. The
improvement of the classical theory of plates by the taking into account of
results of the researches, carried out by authors is recommended: influence of
sites number on plates calculation results on axisymmetric fluctuations;
influence of Poisson's ratio on plates calculation results on axissymmetric
fluctuations; influence of shear strain and masses rotary inertia on plates
calculation results on axisymmetric fluctuations, etc. Bibl. 9.
Engl.; sum. in Russian.