¹4 (45), 2011





Dinamical research of manipulator with taking into account elastic links with concentrated masses. N. Davitashvili. Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 13-24, (Engl.).

Is stated the dynamical analysis of planar manipulator with closed chains with taking into account elasticity of links with concentrated masses. For carrying out the comparative analysis dynamical research is conducted with rigid links as well as with elastic ones. The method of definition of coefficient compliance coefficient of manipulator is given. The describing motions of motors, input links and concentrated masses are obtained. There are preconditions for study of oscillating process of gripper. As examples are given results of synthesis of manipulator, which gripper can move on straight line. 5 ill. Bibl. 11. Engl.; sum. in Russian.


On the Mechanics of Valve Spring Rotation in Internal Combustion Engines depending on the Rotational Speed of the Camshaft. Peter Taubmann, Igor Zeidis, Klaus Zimmermann, Hans-Juergen Schorcht, Ulf Kletzin. Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 25-36, (Engl.).

From practice, it is known that high dynamic stressed valve springs rotate around their axis. The direction of rotation depends on the excitation frequency. Therefore the direction of rotation changes during the usage of valve springs for example in a modern combustion engine. This article presents an analytical expression for the angular velocity of the spring in the stationary regime using a mechanical model with two degrees of freedom. The results are obtained by asymptotic methods with the assumption of small friction between valve spring and valve spring seat.

An experimental setup allowing the measurement specific parameters of the spring rotation was developed for the evaluation of the analytical and numerical results. Finally the described phenomenon is discussed in the global context of the dynamic behaviour of mechanical systems near the resonance. 11 ill. Bibl. 8. Engl.; sum. in Russian.


characteristic differential equations 0f additional Break-contact-break (B1C2B3) motion of optimal brake leverage transmission. G. Sharashenidze, T. Natriashvili, M. Glonti.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 37-44, (Engl.).

In the work is presented differential equations of additional motion of passenger rail-cars optimal brake leverage transmission, when from three joint connections in the first is free motion, in the second - contact, and in the third – free motion. At generation of differential equations are applied Lagrangian equation of second order and dynamical model of optimal leverage transmission. The dynamical loadings of transmission links an impact of brake force on whole system are taking into account. The generalized force represents the function of existing in joint connections reaction and friction forces and with geometrical parameters of transmission defines the structure of differential equations of additional motion. 1 ill. Bibl. 13. Engl.; sum. in Russian.


MODAL ANALYSIS OF THE ELEMENTS AND SUB-ASSEMBLIES OF CUTTING-OFF MACHINES WITH ENDLESS BANDSAW. W. Kalinski, J. Wojnarowski. Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 45-51, (Engl.).

The excited mechanical vibrations affect unfavourably the efficiency of the process as well as the tool life of the teeth of the saw and the state of the surface of the cut object. The paper presents the results of measurements of the acceleration of vibrations in selected sub-assembles of the cutting head, as well as the results of modal analysis, curried out in order to identify the mechanical properties of the band-saw. 10 ill. Bibl. 5. Engl.; sum. in Russian.


DETERMINATION OF THE DEFORMATION ZONE PARAMETERS FOR  LONGITUDINAL TUBE ROLLING IN THE ROUND PASS ON THE DRAWN  BACK  CONICAL MANDREL.  R. Adamia, T. Natriashvili, S. Mebonia, M. Mikautadze.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 52-57, (Engl.).

In article the main deformation   and  forces  parameters of the deformation zone for longitu-dinal  tube rolling in round pass on the drawn back conical mandrel is determined.  Received   dependences  allows  to calculate above mentioned parameters at the designing of the tecnologi-cal process of the tube rolling. 3 ill. Bibl. 5. Engl.; summ. in Russian.


Experimental research reflecting mesh of reflector. E. Medzmariashvili, O. Tusishvili, M. Sanikidze, N. Tsignadze, G. Gratiashvili, G. Tabagari, S. Nemsadze, I. Gobejishvili.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 58-64, (Engl.).

The work is intended to reduce elasticity, arrangement of tensioners and to experimental research of its tensioning force. Here is determined average meaning of mesh reduce elasticity, also the dependence nature among tensioning force and tangency points of displacement of tensioners on mesh. 7 ill. Bibl. 3. Engl.; sum. in Russian.


operational characteristicS of TANDEM-wheeled TRACTOR aggregate on SLOPE. R. Makharoblidze, I. Lagvilava, O. Asatiani, A. Kobakhidze.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 65-71, (Engl.).

Is given the theoretical analysis of wheel’s skid impact on lateral displacement of the tandem-wheeled tractor aggregate on slope. Is derived a formula for calculation of lateral displacement of aggregate in a function of displacement across the slope. This gives the possibility to analytically determine the effect of lateral skid and angle of slope on such operational characteristics, as pulling force and pulling power of tractor, the coefficient of utilization of pulling force, the actual speed of tractor, coefficient of utilization of speed, time, etc. It is shown that application of experimental tandem-wheeled drive on tractor reduces lateral skid of the aggregate on a slope and therefore improves operational characteristics. Results of the study would be applied the planning machinery works on the slope.  2 ill. Bibl. 3. Engl.; sum. in Russian.


Transformation of deployable bridge mechanisms. V. Gogilashvili, E. Medzmariashvili, M. Sanikidze, G. Medzmariashvili. Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 72-76, (Engl.).

Paper discuss the force analyses of transformation of deployable bridge mechanisms, e.g. – transformation of bridge mechanisms on time of contour deformation and, beat and damping on last stage of transformation. Received results are giving possibility to build an image of system transformation for the last stage and discuss about dynamic process of complete system. 5 ill. Bibl. 4. Engl.; sum. in Russian. 


RESULTS OF CALCULATION OF COMPOSITE FUSELAGE AIRCRAFT BASED OSCILLATIONS ARISE DURING TAKEOFF AND CREEP. A. Dumbadze, Yu. Kanchaveli. Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 77-84, (Engl.).

Optimal values of outer radius, area and bending stiffness of the cross sections of    carbon-fiber fuselage sections of CMU-1 for a reinforcement , taking into account creep, random, and other factors causing variations (large roughness of the runway, a gust of wind during takeoff, a large gradient atmospheric pressure and temperature, etc.). Accounting for creep and vibrations arising in the fuselage of the main passenger jet made of carbon fiber CMU-1 will lead to safer, fatigue and noise fuselage, as well as its life. 2 ill. Bibl. 6. Engl.; sum. in Russian.


mode of deformation of double curvature  depressed shell with cut. G. Kipiani, F. Verulashvili, M. Todua, G. Nozadze.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 85-88, (Engl.).

Is stated solution of problems of synthesis of sewing-machine thread takeup joint mechanisms (together with carrying needle) according the given of output links law of motion. The problem is solved by two – grapho-analytical and analytical methods. In the first case, according the given output links law of motion (needle) are defined the sizes of links, and in the second case, according the given thread takeup and needle law of motion are analytically defined all parameters of the mechanism. The received expressions and the equations are realized by computer machinery. 2 ill. Bibl. 3. Engl.; sum. in Russ.


equation for entropy of open non-equilibrium systems A. Aptsiauri. Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 89-96, (Engl.).

In the work are considered the features of entropy change in open and closed thermodynamic systems, in the presence of mechanical and thermal disbalance. It is shown that in contrast to closed systems, in open thermodynamic systems, surface effects would leads to a decrease in entropy that is contrary to the principle of entropy steady increase in the heat-insulated systems.  4 ill. Bibl. 5. Engl.; sum. in Russian.


THE MATHEMATICAL MODELING OF THE MIGRATION OF POLLUTANTS IN SUBTERRANEAN WATERS. K. Tskhakaia, M. Khetsuriani. Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 97-102, (Engl.).

  There is considered the mathematical modeling of the planned filtration flows of subterranean waters with the existence of water intake for the purpose of determination of pollutants’ migration directions. There is shown that the volume of the water intake exercises a significant influence on possibility of penetration of pollutions into the water intake area.  4 ill. Bibl. 2. Engl.; sum. in Russian.


limiter - absorber of axial movement in running gear of new type gantry crane. m. Shilakadze, V. Kartvelishvili, M. Barbakadze, D. Bakradze, I. Jamburidze.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 103-107, (Engl.).

In the article is stated the specific solution of improve of reliability process in running gear of gantry cranes at its operating process. In particular, is considered and grounded the advisability of application of ring springs in role of absorber in the possible axial displacement originated at operating process of the crane with modernized running gear. The calculations are carried out. 1 ill. Bibl. 4. Engl.; sum. in Russian.


THE WEAR OF ALUMINIUM DUCTILE IRON DURING DRY FRICTION. N. Khidasheli, G. Beradze, G. Khvichia.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 108-113, (Engl.).

In the present work there are given the results of experimental investigations of contact fatigue and the wear of deformable high strength austempered ductile irons - ADI class aluminum cast iron depending on the phase ratio in metallic matrix. The wear rolling and rolling with creep tests carried out on the specimens tempered till different levels of hardness showed strong dependence of contact fatigue and the wear on the amount of retained austenite in the samples with optimal ratio, required for keeping the high wear resistance of wearing surfaces, of bainite and martensite phase components in the matrix structure.  2 ill. Bibl. 8. Engl.; sum. in Russian.


On studying of dynamics of electro hydraulic control systems course and position of the vessel. T. Mchedlishvili, V. Kiria, K. Amkoladze, R. Diasamidze.  Scientific Journal of IFToMM “Problems of Mechanics”. Tbilisi, 2011, ¹ 4(45), pp. 114-117, (Engl.).

Control systems of course and position of the vessel, ensuring performance of fundamental problem of navigation that consists in the precise and safe ship control in accordance with the assigned task and specified quality criteria, represents between marine automated drives the most complicated multiple connected multi-mode regulatory system. In connection with the above mentioned is very urgent task of improving the performance of dynamic studies of considered system. In this paper are considering the problems of constructing the initial laws for the application of method of synthesis by a given transition processes.  1 ill. Bibl. 4. Engl.; sum. in Russian.