SUMMARIES

¹1(42), 2011

Dynamical analysis of robot planar hingEd actuator mechanism.
N. Davitashvili.
Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 8-15, (Engl.).

Is given the dynamical analysis of robot’s planar hinged actuator mechanism formed on the basis of five-bar mechanism with two degrees of freedom and consisting three grippers. Is given the operating principle and is shown the possibilities of its operations in five modes. For one case of actuator mechanism’s and grippers operation are obtained formulae of kinetic energy, reduced moments and non-linear second order differential equations by solving of which are defined real laws of motion of  mechanism when all links are absolutely rigid.  2 ill. Bibl. 7. Engl.; sum. in Russian.

Designing Fundamentals of Investigation Equipment of Rotors with the Parameters of Variable Geometry. R. Turmanidze, Î. Rukhadze, R. Bidzinashvili, Å. Rukhadze. Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 16-23, (Engl.).

In this article the brief review of the state of question of designing of the investigation equipment of rotors with the parameters of variable geometry (the stand for dynamic tests of the VGR) is given. By calculation and experimental ways the dependences of consumption power from values of rotational speeds are determined. Also the hydro-system parameters of the stand for dynamic tests of the VGR are determined. 4 ill. Bibl. 9. Engl.; sum. in Russian.

comparative analysis of dynamic loadings in joint connections with clearances of optimal brake linkage transmission. G. Sharashenidze, S. Sharashenidze, P. Kurtanidze.  Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 24-32, (Engl.).

In this paper is carried out comparative analysis of arising in passenger car’s optimal brake leverage transmission’s joint connections with clearances friction and reaction forces. A dynamic model of optimal brake leverage transmission with clearances is applied for research. The additional contact motion of system is selected for the carrying out of comparative analysis, when transmission rod endpoints represent the internal elements of joint connections with clearances. Are developed the equations of equilibrium and are obtained the functional interdependence of dynamic loadings in the joint connections with clearances, according of dynamic loadings distribution for contact points of rods and vertical suspensions. In the expressions of comparative analysis are provided the significant geometric values of clearances as well as the phenomena of dry, wet and quadratic friction in the joint connections. For the arbitrary kind of friction phenomenon would be selected the values of developed by brake cylinder and brake shoe pressing force on the car’s wheel. The mathematical formulation of the dynamic loading’s comparative analysis gives the possibility to apply the principles of analysis in the sol of problems of kinematic and dynamic synthesis of optimal brake leverage transmission. 1 ill. Bibl. 17. Engl.; sum. in Russian.

Structural Models of Random Vibration’s Experimental Data. C. Mert, A. Milnikov. Problems of Mechanics”, Tbilisi, 2011, ¹ 1(42), pp. 33-36, (Engl.).

A method of analysis of mechanical ossilations’ experimental data’s (experimental time series) internal structures based on Singular Spectrum Analysis is discussed. It has been shown that in the case when the Time Series contains deterministic additive components rank of the trajectory matrices equal to number of parameters of the components. Also it was proved that both eigen and factor vectors repeat shapes of the additive components and both eigen values and eigen vectors can be divided into additive groups. Some useful patterns of deterministic components were identified, which permit to provide graphical analysis of times series Internal Structures. Bibl. 12. Engl., sum. In Russian.

INTERACTION OF THE UNDERCARRIAGE OF ADAPTIVE TANDEM-WHEELED SEIF-PROPELLED CHASSIS WITH THE SOIL BASED ON THE RHEOLOGICAL MODELS.
R. Makharoblidze, I. Lagvilava, O. Asatiani, A. Kobakhidze.”Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 37-44, (Engl.).

The work contains the theory of the interaction of the undercarriage of adaptive tandem-wheeled self-propelled chassis with the soil. A rheological model of Voigt is used as the deformation law of soils. A calculation formula for the soil deformation by considering the relative location of the front steering and rear driving tandems wheels is deduced. A numerical example is used to demonstrate the reduction of the depth of trace after the passage of three tandem wheels of an adaptive chassis as compared with that of a serial chassis. 1 ill. Bibl. 4. Engl.; sum. in Russian.

RUNNING WHEEL OF hoisting CRANE WITH CHANGED shape OF ROLLING SURFACE. M. Shilakadze,  V. Kartvelishvili,  M. Barbakadze, I. Jamburidze.  Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 45-48, (Engl.).

In the article is given the development of new designs of roll surface of gantry cranes running wheels. The existing running wheels of hoisting cranes are cylindrical in shape and lateral flange on two sides, which are extensively worn. With the change of the hoisting crane’s wheels roll surface’s shape of the and giving for it the possibility of axial movement is achieved the minimizing of transverse forces that arises at crane moving due the deviations of wheel, rail or railway geometrical parameters from the permissible values of technical standards. As a result is reduced friction between the rolling-sliding contact surfaces of wheel and rail, and consequently decrease the additional vibrations of crane’s metalware, thus is achieving the improvement of wear resistance and crane’s running wheel and total operating life. 2 ill. Bibl. 8. Engl.; sum. in Russian.

ELECTRICAL CONDUCTING AND PARAMAGNETIC PROPERTIES OF CHANNELS FORMED AFTER LASER BEAM IRRADIATION OF SOME POLYMERS. J. Aneli, E. Semiletova, N. Bakradze, T. Dumbadze.  Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 49-53, (Engl.).

Formation of electrical conducting channels with paramagnetic properties on the surface of three type polymer plates (phenol-formaldehide and epoxy resins, polyacrylonitril) under influence of CO2 laser irradiation at the presence of air have been studied. It is shown that the magnitude of surface resistance of the investigated polymers depends on polymer type and irradiation energy. The appearance of electrical conducting regions in the polymer materials is due to laser-chemical transformations of macromolecular physical and chemical structures near the polymer plate surfaces, leading to formation of double conjugated bonds. These structures are characterized also with paramagnetic properties- by method of ESR the free radicals are discovered in the transformed regions of polymers. The obtained results practically are analogous to ones obtained in such polymers after thermal treatment at high temperatures. However here are some advantages. At last case for obtaining of conducting materials on the base of dielectric polymers it is necessary the use of high vacuum. Besides of such method don’t allows the formation of conducting channels with desired square and configuration on the surface of polymer plates in very short time (about several seconds) at present of air.  5 ill. Bibl. 6. Engl.; sum. in Russian.

TO THE THEORY OF TEA LEAF TWISTING PROCESS: CRITERIA OF TWISTING AND AN EQUATION FOR THE DEGREE OF THE TEA MASS TWISTING. A. Tvalchrelidze, B. Kankadze. “Problems of Mechanics”. Tbilisi. 2011, ¹ 1(42), pp. 54-60, (Engl).

For the closure of system of equations, modeling the tea leaf twisting process, it is necessary to apply an additional equation describing the time variation of the twisting degree at a material point of the mass. This equation must contain the so-called twisting criterion. There are proposed several admissible versions for this criterion. 5 ill. Bibl. 2. Engl., sum. in Russian.

Investigation of fuel economy of gas turbine in hybrid cars. M. Ben Chaim, M. Brand, O. Gelashvili, N. Navadze.  Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 61-66, (Engl.).

Though since recently, hybrid cars are having acceptable technical parameters. Until now, hybrid cars have been basically using traditional internal combustion engines, either working on diesel or gasoline, due to their state-of-the art nature and relatively high thermal efficiency. However, when analyzing engine operation modes in hybrid cars, and more particularly, their ability to operate in an optimal mode, a gas turbine usually comes to mind, which is comparable to other thermal engines due to its exceptional technical properties. Determining its performance in hybrid cars in terms of fuel economy alone is technically incorrect, since all aspects of this technical solution shall be taken into account. This paper is an attempt to evaluate the performance of gas turbines as a main source of energy in hybrid cars by means of system analysis.  1 ill. Bibl. 16. Engl.; sum. in Russian.

logistic system of transport companies financial flows management. O. Gelashvili, G. Tsertsvadze, N. Butkhuzi.  Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 67-69, (Engl.).

In the work is considered the logistic system of transport companies financial flow management, which is based on the method of actual analysis and gives the possibility in arbitrary reporting period to determine the financial condition of transport companies. The developed logistic system provides transportation companies results management by taking into account affecting financial flows current factors. Also due the changes ​​of these factors values to fulfillment of transport companies financial forecasting.  Bibl. 7. Engl.; sum. in Russian.

Low rank tensor approximation algorithm in Singular Value Decomposition Problem. C. Mert, A. Milnikov. Problems of Mechanics ”, Tbilisi, 2011,
¹ 1(42), pp. 70-79, (Engl.).

A new method of computation of singular values and left and right singular vectors of arbitrary non-square matrices has been proposed. The method permits to avoid solutions of high rank systems of linear equations of singular value decomposition problem, which makes it not sensitive to ill-conditioness of decomposed matrix. On base of Eckart-Young theorem, it was shown that each second order r-rank tensor can be represent as a sum of the first rank r-order “coordinate” tensors. A new system of equations for “coordinate” tensor’s generators vectors was obtained. An iterative method of solution of the system was elaborated. Results of the method were compared with classical methods of solutions of singular value decomposition problem. Bibl. 9. Engl., sum. In Russian.

About development of special technical schedule providing in post-soviet countries railway transport and its infrastructure’s safety.
M. Moistrapishvili, E. Moistrapishvili, N. Rurua. “Problems of Mechanics”. Tbilisi, 2011, ¹ 1(42), pp. 80-86, (Engl.).

After the separation of former Soviet Union’s unified railway network, CIS and Baltic countries have become an urgent necessity to develop a special regulation on the technical safety of railway transport and its infrastructure.

In this document by chapters and paragraphs are presented the all conceivable main problems, are given the clarifications and clarification of basic terms that are required for the development of technical rules of national special safely railway transport and its infrastructure, with taking into consideration and concordance with international approach. This approach gives the possibility to provide a high degree of safety and to minimize the concomitant risks.

Regulations of ensuring the safety railway transport and its infrastructure must meet the following requirements:

• Basic (minimum necessary) requirements to ensure the railway transport safety;
• Basic requirements of the rail ¬ road transport subsystem’s safety;
• Providing of forms, outlines and rules of evidence requirements in line;
• Ensuring the requirements of the compliance rules of safety controls on the railway facilities.

Thus the task of development of special technical regulations of railway transport and its infrastructure safety must be mandatory for the post-Soviet countries for integration of their transport systems in the world transport system is urgent and mandatory. 2 ill., Bibl. 3 Engl.; sum. in Russian.

definition of directions of georian railway passage technical capacity development in relation of cargo TRAFFIC CHARACTER.
P. Kenkadze, A. Sharvashidze, G. Guramishvili, G. Lomouri, K. Sharvashidze.
Problems of Mechanics”. Tbilisi, 2011, ¹ 1 (42), pp. 87-90, (Engl.).

in the conditions of transport market repartition and functioning of new freight directions in the paper is considered freight character of Georgian railway passage and prediction of perspective cargo traffic, possibility of direction of technical development definition. 1 ill. Bibl. 3. Engl.; sum. in Russian.