# Summaries

The influence of a clearance and a friction force on the basic characteristic parameters of the operation mechanism of a refrigerator railcar’s diesel engine.

N. Davitashvili, G. Sharashenidze, R. Morchiladze, S. Sharashenidze. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 9 – 16, (Engl.).

The phenomenon of change of dynamic and kinematic parameters caused by the clearance and friction forces in hinged joints of operational mechanism with clearances of refrigerator railcar’s diesel engine has been investigated. The change of characteristic parameters is considered for all hinged joints and given mechanism. Theoretically investigated parametric change is confirmed by the values of results by machine computation. The results of investigation are given by diagrams and tables for different values of the clearance and friction force. The results of investigation give optimal value of clearance in all kinematic pairs for reliable work of the mechanism. 5 ill. Bibl. 11. Engl.; summ. in Russ.

Curve-following for redundant manipulators with obstacles: feasibility analysis and solutions. Ph. Wenger. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 17 – 26, (Engl.).

This paper provides a practical solution to the following problem. Given a curve defined in a robotic site with obstacles and given a redundant manipulator with joint limits in the site, is the manipulator end-effector able to follow the prescribed curve in a continuous motion? If yes, find all the feasible solutions to follow the curve. If not, find the feasible and infeasible parts of the curve and for each feasible part, find all the solutions to follow this part. A new practical feasibility condition is stated by reformulating the feasibility analysis in a (r+l)-dimensional space where r is the manipulator redundancy. This condition uses the notion of aspects by regarding the manipulator as non redundant with respect to an augmented task space. The method complexity is independent of the manipulator degree of freedom. The method has been implemented for r=1 using quad-trees but it can be used for r=2 with oct-trees. Application examples are shown with a 3R planar manipulator and with a 6R welding manipulator. 10 ill. Bibl. 15. Engl.; summ. in Russ.

Kinematic analysis of a family of 3R manipulators. M. Baili, Ph. Wenger, D. Chablat. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 27 – 32, (Engl.).

The workspace topologies of a family of 3-revolute (3R) positioning manipulators are enumerated. The workspace is characterized in a half-cross section by the singular curves. The workspace topology is defined by the number of cusps that appear on these singular curves. The design parameters space is shown to be divided into five domains where all manipulators have the same number of cusps. Each separating surface is given as an explicit expression in the DH-parameters. As an application of this work, we provide a necessary and sufficient condition for a 3R orthogonal manipulator to be cuspidal, i.e. to change posture without meeting a singularity. This condition is set as an explicit expression in the DH parameters. 7 ill. Bibl. 15. Engl.; summ. in Russ.

Simulation of unavailability of the off-shore unit’s power plant system with use of selected algorithms. L. Chybowski, Zb. Matuszak. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 33 – 47, (Engl.).

The selected power plant system of a multi support off-shore vessel exploring seabed was used for a simulation of the unavailability of the system. The analysis was performed on the basis of a fault tree for fuel supply system by the upper bound approximation and with the use of the exact calculation algorithm. 14 ill. Bibl. 14. Engl.; summ. in Russ.

Spinor evaluation of Euler’s angles. A. Milnikov, H. Onal, R. Partskhaladze, I. Rodonaia. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 48 – 53, (Engl.).

In the article, using spinor representation of orthogonal transformations, the equations, for generalized rotations are received. The rotations are defined as set of all possible rotations, both with zero, and non-zero centers which carry out transformations of initial 3-dimensional point into a final. The expressions between second order complex unitary transformations matrice and real orthogonal matrice of rotations in L3 are received, that allows easily calculating of corresponding Euler’s angles. Bibl. 4. Engl.; summ. in Russ.

Problems of moving mechanical objects adaptive control. C. Erguven, A. Milnikov, I. Rodonaia, A. Suladze. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 54 – 58, (Engl.).

Various problems of movement control of mechanical objects: Problem of acceleration, problem of bringing, problem of time-dependent control and problem of time-independent control have been considered and solved. The simple expressions for relevant optimum phase trajectories and algorithms of adaptive movement control have been obtained, which allows their effective practical realization to be carried out. The connection between given approach and method of dynamic programming is shown. Bibl. 4. Engl.; summ. in Russ.

substantion of rational combination of active and passivE worKing members in compound soil-working plant. R.Makharoblidze, K.Torikashvili, G.Charakishvili. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 59 – 62, (Rus.).

The methods of substantiation of rational interlocation of active and passive working members in compound soil-working plant is worked out in case of milling drum cutter stroke in the moment of maximum stressed state. The working modes of cutter and cultivator tooth operation are substantiated. A numerical example is given. 2 ill. Bibl. 2. Russ.

Principles of choice of parameters of equipment with rotary operating elements. O. Bedia. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 63 – 67, (Rus.).

The mechanical-technological principles of choice of design and kinematic parameters of equipment for inter-vine soil cultivation at vineyards, with deriving an equation of mechanical trajectory of rotary operating element and uncultivated area around the trunk, based on the said parameters are presented. 2 ill. Bibl. 2. Russ.

The problems of working out of new mathematical models of the constructions’ deformation. G. Lagundaridze. I. Khartishvili, Z. Seskuria, D. Tavkhelidze, S. Bliadze. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 68 – 73, (Rus.).

The problems of working out of new mathematical models of the constructions’ deformation is considered. The physical dependences is listed for the membrane consisting of a layer of nonlinear – elastic material with a definite step of the iterational process and the expression for theirs definition is received. 1 ill. Bibl. 2. Russ.

Rise of efficiency of the process of the details pressing in closed volumes by application of complex schemes of superposition of ultrasonic oscillations.

S. Christaphoryan, B. Balasanyan, A. Artunyan. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 74 – 77, (Rus.).

The technological capabilities of New method of rise of efficiency of the process of pressing of powder materials and of plastic deformation of materials in closed volumes by application of complex schemes of superposition of ultrasonic oscillations are considered. The different schemes of ultrasonic pressing, including for the first time realized pressing with tensional – radial ultrasonic oscillations of a matrix and axial oscillations of a puncheon, and with axial oscillations of a puncheon and tensional - radial ultrasonic oscillations of a matrix with rotatable matrix were investigated. 1 ill. Bibl. 3. Russ.

High technologies for development of underground space. K. Churadze, Z. Kviriashvili. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 78 – 82, (Rus.).

The paper presents retrofit diagram of authors Fener-Paher interference of rock with set, which gives us understanding of structure of rock and set total failure. From the basis of diagram was created analytical method of underground construction calculation, taking into account technology of tunnel construction. Method is on basis of hypothesis of interference deformation, within reach concept with using of flat stress problem, where capacity of problem takes in account functions of front effect. 2 ill. Bibl. 6. Russ.

The boundary problem for the ball and the infinite space with the spherical cavity of viscous incompressible fluid. K. Skhvitaridze, M. Khmiadashvili, G. Karseladze. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 83 – 88, (Rus.).

It is considered a boundary problem for the ball and the space with the spherical cavity of viscous incompressible fluid’s steaty flow. It is proved the theorem of solution’s uniqueness. Based on the solution of Navie-Stock’s homogeneous differential equations system, the solution of the given problem is presented in the form of absolutely and uniformuly convergent series. Bibl. 5. Russ.

Pulsatory flow of incompressible viscous fluid in the rigid horizontal tube with taking into account a frictional force. V. Tsutskiridze. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 89 – 94, (Rus.).

The title problem is studied for the case in which the flow of viscous liquid is due to the pulsation of pressure gradient. The pressure function may be an arbitrary function of time variable. The physical characteristics of liuquid movement are found. 3 ill. Bibl. 9. Russ.

Expression of general solution of micropolar viscous incompressible fluids stationary stream’s homogenous equations system. M. Kharashvili. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 95 - 99, (Rus.).

General solution formula of viscous incompressible fluid’s stationary stream’s homogenous equation system is derived expressed by two harmonic and one metaharmonic functions. Bibl. 3. Russ.

CALCULATION IN SHIFT OF GENTLE MEMBRANES AND PLATES WEAKENED BY RIGHT-ANGLED CUTS. N. Vanishvili, T. Kochiashvili, G. Lejava. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 100 – 106, (Rus.).

The methods of calculation of a gentle membranes with cuts is considered. The general method of approach to work out a solving diffential equations is and the different simplified variants is stated as a particular cases. Bibl. 4. Russ.

Mathematical model of coastal currents of the black sea in Poti’s region. I. Saginadze. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 107 - 110, (Rus.).

The mathematical model of the Black Sea in Poti’s region is proposed. The algorithm of the numerical solution of a problem is worked out. 1 ill. Bibl. 4. Russ.

Development of mathematical model and new method for appraising of dust capacity and dust permeability of textile linen. Z. Maghlapheridze, E. Buadze. “Problems of Applied Mechanics”. Tbilisi, 2004, № 2(15), pp. 111 – 114, (Rus.).

In the article at the development of appraising method of dust capacity was used the simplified mathematical model of dust capacity of textile materials, taking into consideration the transposition, research of linen with the mass “m” in surface. The main factors which must be taken into consideration by model are determined. By the researching result the appraising method was developed, which makes the work on the device easier, and finally gives more exact data in comparison with the existent methods. 1 ill. Bibl. 4. Russ.