¹3(52), 2013



research of operational characteristics of crank-piston mechanism of applied in oil and gas pipe - lines pumps. N. Davitashvili, V. Bakhshaliev, V. Abaishvili.  Problems of Mechanics”. Tbilisi, 2013, ¹ 3(52), pp. 5-25, (Engl.).

Is stated a study of influence of operational characteristics (friction, clearance, wear) of crank-piston mechanism with clearances on the laws of motion, velocity, and acceleration of the crank, rocker and piston of mechanism. With the application of computer technology is given an analysis of the operational characteristics of ideal and real mechanisms with application of differential equations of basic and additional motions of mechanism (contact-contact, contact break, break-contact and break-break). The numerical methods for solving the problem of dynamic analysis of mechanisms are considered. The effect of operational characteristics on the motion of kinematic pair’s elements on the change of reaction forces and the laws of crank motion are revealed.

The carried out studies gives the possibility with taking into account of friction to determine and select (establish) the optimum clearance dimensions conducive to reliable and durable operation of piston pump and their mechanisms.   11 ill. Bibl. 17. Engl.; sum. in Russian.



dynamical analysis of crank-piston mechanism with consideration of impacts in kinematic pairs with clearances. N. Davitashvili, V. Bakhshaliev, V. Abaishvili.  Problems of Mechanics”. Tbilisi, 2013, ¹ 3(52), pp. 26-44, (Engl.).

Is stated the dynamic investigation of crank-piston mechanism with taking into account of impacts in kinematic pairs with clearances. Are defined the velocities of colliding masses of links before and after impact and restoring coefficients. In order for assessment of changes in vectors components are applied the following hypotheses: Newton, on absolute smoothness of colliding links, on instantaneous and dry friction ratio. Is determined that with increasing of restoring coefficient the values of reaction forces and numbers of chain interruptions are decreasing. The changes in dependency of values of clearances are revealed.  The results for selection of optimal clearances providing the reliable and durable operation of a piston machines, as well as their mechanism are given.   11 ill. Bibl. 23. Engl.; sum. in Russian.



DEFINITION  OF  DEFORMATION RATE IN THE  HELICAL PIERSING OF  BILLETS. T. Natriashvili, S. Mebonia, M. Mikautadze. “Problems of Mechanics”. Tbilisi, 2013, ¹ 3(52), pp. 45-48, (Engl.).

          In article the formulas for calculating the rate of deformation in the helical piercing  of tube billets in the hollow on mills with barrel rolls is  proposed. Analysis of the formulas show  that the rate of deformation is dependent on the geometric and kinematic parameters of the rolling process. 2 ill. Bibl. 3. Engl.; sum. In Russian.


THE MATHEMATICAL MODELING OF PLASMA-ARC CUTTING PROCESS. A. Tvalchrelidze, P. Kipiani, K. Tskhakaia. “Problems of Mechanics”. Tbilisi, 2013, ¹ 3(52), pp. 49-54, (Engl.).

Based on the fundamental laws of conservation, there is developed the mathematical model of stationary process of plasma-arc cutting in a first approximation. On the basis of this model, there are carried the computational experiments the results of which fit well with the known experimental data.  There is observed a significant impact of screening action of liquid metal film on cutting process. 3 ill. Bibl. 4. Engl.; sum. in Russian.


GENERATION OF ENERGY FROM EQUILIBRIUM ENVIRONMENT – THE ABILITY RELEVANCE AND PROSPECTS. A. Aptsiauri. “Problems of Mechanics”. Tbilisi, 2013, ¹ 3(52), pp. 55-59, (Engl.).

In the article is shown that if in the thermodynamic cycle is carried out the heat-insulated process of apparent cooling, with heat absorption in energy of perturbations, and the reverse process occurs in conditions of perturbation synchronization, such thermodynamic cycle would continuously generate usable energy from the heat. As an example, is stated that in water flow, at occurrence of turbulence and cavitation, it appears possibility of useful energy generation. 1 ill. Bibl. 7. Engl.; sum. in Russian.


CONTROL OF 3-DOF PLANAR PARALLEL ROBOT. Vo Dinh Tung, S. Kheylo, V. Glazunov. “Problems of Mechanics”. Tbilisi, 2013, ¹ 3(52), pp. 60-64, (Engl.).

This paper deals with control of 3-DOF planer parallel robot.  The control algorithm of parallel robot satisfying partial decoupling between translation and orientation degrees of freedom is synthesized. Simulation result of control algorithm in desired trajectory of end-effector of robot is shown. Here parallel manipulator control algorithm while intersecting singular zones is considered. 12 ill. Bibl. 5. Engl. sum.; in Russian.


       CONTROL OF MOBILE ROBOT BY MEANS OF CELL PHONE. V. Margvelashvili, R. Partckhaladze, M. Ben Chaim.  “Problems of Mechanics”, Tbilisi, 2013, ¹ 3(52),  pp. 65-67, (Engl.).

In article the new method of remote control of terrestrial robotic vehicles is suggested. The method is based on a on the cell phone applications for the movement control problems. It shown that all necessary control operations can be easily done by means of simple pressing on the cell phone buttons, and that the circuit remote control is quite simple and does not require the development of complex knots. Also the suggested method provides the wide working range of control (it is as large as the coverage area of a cellular communications provider) and elimination of influence of the outer transmitters. Bibl.3. Engl.; sum. in Russian.