3(24)2006

S U M M A R I E S

 

INVESTIGATION OF OWN OSCILLATION FREQUENCES OF THE MECHANISMS OF SEWING-MACHINES. N. Davitashvili, V. Abaishvili. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 9-16, (Engl.).

On a base of the analysis of hinged mechanisms of sewing-machines, working in ciclic and coordinated manner, it is given a dynamic model characterizing a principle of combination of technological operations. The method of determination of own oscillation frequences of the mechanisms of sewing-machines is developed. The oscillation of the system of mechanisms is investigated theoretically and by use of computational techniques. 3 ill. Bibl. 14. Engl.; summ. in Russ.

 

DESIGN AND TESTING OF A LASER SYSTEM DEVELOPED FOR TWO-DIMENSIONAL DISPLACEMENT DETECTION. G.A. Danieli, D. Mundo, F. Colacino, G. Fragomeni. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 17-25, (Engl.).

The paper presents a new instrument for three-dimensional displacement detection, consisting of two basic units: the first unit uses a laser-beam to detect the displacement of a point in two directions perpendicular to the beam itself; the second one employs a laser interferometr device in order to detect displacements in the third direction (i.e. the direction of the laser beam). In particular, the 2D unit is composed of a CCD camera facing a dark screen on which the incoming laser beam is focused. A filteredthrough image on the CCD sensor is thus generated. The image is transmitted to a computer in order to calculate its centre of mass. When a significant image displacement is detected, a pair of computer-controlled step motors is used to reposition the system. The paper describes the entire system, composed of both 2D and 1D displacement-detection devices. A prototype of the 2D device is built and used to test the precision and reliability of the proposed solution. Results demonstrate that the device is highly sensitive and capable of detecting fractions of a millimetre of displacement in each direction. The subsequent computer-controlled repositioning is carried out with an error which is negligible with respect to the displacements the application understudy as characterized by. 7 ill. Bibl.11. Engl.; summ. in Russ.

 

ONE TWO-DIMENSIONAL REVERSE PROBLEM OF THE NONLINEAR THEORY OF ELASTICITY. B. Midodashvili. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 26-30, (Engl.).

In this work, a question on the effective solution of one class of two-dimensional reverse problems for the nonlinear theory of elasticity for harmonic type material is investigated. The case, when tangential normal efforts vary along unknown contour according to e certain rule is examined. For the solution of problem it is used the complex representation of stress and deformation fields through two analytical functions. The exact solution of problem is obtained. An example is considered. Bibl. 5. Engl.; summ. in Russ.

 

ABOUT REFORMATION ISCHLINSKI'S THREE-ELEMENTS REOLOGICAL MODEL. A. Dumbadze, J. Kanchaveli. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 31-37, (Russ.).

The five-elements reological model displaied an example of subsequent development of such three-elements Ischlinski's model for description stress-strained position for constructive plastics (CP) is propoused. This model qualitatively and enough quantitatively discribes the creeping of CP in low stressed conditions likewise in a high. 2 ill. Bibl. 5. Russ.

 

THE STEADINESS OF LAMINATED AIRCRAFT WINGS PANEL IS MADE USE OF CONSTRUCTIVE FIBROUS PLASTIC WITH REGARD FOR CREEPING. A. Dumbadze, J. Kanchaveli. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 38-45, (Russ.).

The problem for lac of experimental diagrams for total steadiness waste in standard laminated sections and constructures are made use of constructive fibrous plastics (CFP) is determined with due regard for creeping. The calculation is demonstrated for example to laminated aircraft wing's panel produced with fibrous plastic ETF-BM-78. The application of such diagrams permits to heighten safety constructures of CFP which work under compression conditions. 4 ill. Bibl. 6. Russ.

 

TWO DIMENSIONAL PROBLEMS OF MICROPOLAR VISCOUS INCOMPRESSIBLE FLUID STATIONARY MOVEMENT FOR THE CIRCLE AND THE HOLLOW CIRCLE. M. Kharashvili. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 46-50, (Russ.).

The boundary value problems for the circle and the hollow circle are solved using the general representation formula for the homogeneous differential equations system solution of stationary movement of micropolar viscous incompressible fluid. The solution is obtained in the form of absolutely and uniformuly convergent series. Bibl.8. Russ.

 

THE DECISION OF THE BASIC TWO DIMENTIONAL BOUNDARY TASKS OF STATIONARY FLUCTUATION OF A VISCOUS INCOMPRESSIBLE MICROPOLAR LIQUID. M. Kharashvili. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 51-56, (Russ.).

The general representations of the decision is received about system of the homogeneous differential equations of stationary fluctuation of the micropolar viscous incompressible liqued, expressed to two metaharmonious and by one harmonious functions. Be means of this representation are solved regional tasks for a round pipe. The decision of examined tasks is received in the form of absolute and in regular intervals converging lines. Bibl. 2. Russ.

 

THE CONTACT INTERACTION BETWEEN INFINITE ELASTIC STRINGER AND HEREDITARILY AGING STRIP UNDER TANGENTIAL LOADING. S. Mirzoyan, Z. Davtyan. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 57-63, (Russ).

The problem of determination of contact stresses on the joining line of infinite metallic stringer with a polymeric composite strip is considered. It is supposed, that the free side of the stringer is subjected to action of tangential loading, and the bottom side of a strip is rigidly fastened. For a special case when external tangential loading represents two concentrated forces, the numerical analysis is carried out. Recognizing that the stated problem is a modeling problem for determination of the stress state on the joining line of frictional material of brake pads with a metallic basis, the distribution of contact stresses in the zone between applied forces is found. Dependence of contact stresses on the time and the parameters describing rheological properties of composite strip is revealed. 3 ill. Bibl. 6. Russ.

 

ANALYSIS OF THE ADIABATIC CONDITIONS OF A CALORIMETER FOR THE STUDY OF HIGH-TEMPERATURE SUPERCONDUCTORS. M. Chikovani, O. Kiguradze. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 64-68, (Russ.).

It is given the theoretical and experimental investigations of parasitic heat fluxes for determining temperature (critical) of the passage of superconductor from normal state to superconducting state, in the adiabatic calorimetric anstallation. In view of special structural measures conducted in the calorimeter, a summary parasitic heat flux does not exceed 20 microwatts, which indicates the perfection of both the structural and the measuring procedures of the calorimeter. As a result the value of "free temperature motion" of a container is insignificant and does not exceed 0.002-0.003 K/h (practically "zero motion"). 2 ill. Bibl. 3. Russ.

 

INFLUENCE OF CROSS-SECTION CONSTRUCTIONS ON CHANNEL PROCESSES OF WATER-CURRENTS AT MOVEMENT ALLUVIUM STREAMS. I. Inashvili, R. Qruashvili. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 69-72, (Russ).

At movement alluvium streams settlement dependences of characteristics of channel stability, in particular, factor of lateral compression and length which are function of a bias of a water-current, physical and mechanical characteristic of a ground and concentration are received. Bibl. 6. Russ.

 

TO THE QUESTION OF A STATE OF THE PROBLEM OF NATURAL WATERS BY FILTRATION. N. Geladze. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 73-76, (Russ.).

In this work, the analysis of existing physical ideas about the process of filtrational purification of natural waters is given. It is shown that depending on properties and suspension of water the specific processes in the same or different degree can influence of filtration. Accordingly, the state and form of detention of suspension in pores of load will be different. Bibl.4. Russ.

 

ON THE NEED OF SPECIFICATION OF SEISMIC LOADS ON COMPLEX CONSTRUCTIONS. K. Babilodze. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 77-80. (Russ.).

In this work, the investigation of seismic loads on comples constructions is given. For the dynamicity coefficient of ferroconcrete shells it is established that the values of a dynamicity coefficient, accepted within the standards, are understated and must be specified to the side of increase. It is expedient to determine a dynamicity coefficient according to the real accelerograms of the site, where building will be built. Bibl. 5. Russ.

ON NHE THEORY OF STABILITY OF THE RISING PIPE CARCASS OF SKYSCRAPER. S. Daveyan. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 81-86, (Russ.).

In the article on the basis of the worked out theory of calculation are settled rising pipe carcass stability conditions under accounting vicinal wall effect. Has been created the theorem, to adjective the acctptable crippling term. 1 ill. Bibl. 2. Russ.

 

TO THE QUESTION OF DEVELOPMENT OF MULTI-FUNCTIONAL TOWN-PANNING STRUCTURES IN THE RECONSTRUCTED AREA. T. Archvadze. "Problems of Mechanics" Tbilisi, 2006, No 3(24), pp. 87-90, (Russ).

The article deals with the question of development of multi-functional town-planning structures in urban context. The analysis of historical development of multi-functional complexes is given as alternative to mono-functional zoning. Types of multi-functional complexes and their characteristic is given. "Town-planning complex" concept is defined and factors influencing on their formation are analyzed. It was noted, that further multi-functional flexible complexes would be presented as leading functional parts of developing cities. The contents and the form will vary according to new arising requirements of the society depending on a place, tupe and purpose. Bibl. 4. Russ.

 

INFLUENCE OF CULVERT EXCAVATION ON THE STRESS-STRAIN STATE OF DRAINED TUNNEL LINING. K. Kobakhidze. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 91-94, (Russ.).

This research studies the influence of drain gallery (culvert) excavation on the stress-strain state of drained tunnel lining. Calculations based on the Finite Element Method (FEM) show that the drain gallery axcavation causes re-distribution of loads in the rock surrounding the tunnel, which leads to changing of forces in the lining. Namely, in specific geotechnical environment and for specific lining parameters, with the drain gallery located at 5m from the lining, the moments increase up to 150-175% of the initial moments in the most hasardous sections. 3 ill. Bibl. 4. Russ.

 

DEVELOPMENT OF PROCEDURES AND ALGORITHMS OF THE FORMATION OF NOMENCLATURES OF QUALITY INDICES OF SPECIAL PROFESSIONAL PREPARATION FOR CERTIFICATION OF AVIATION OPERATING PERSONNEL. Z. Kandelaki. "Problems of Mechanics". Tbilisi, 2006, No 3(24), pp. 95-100, (Russ.).

In this work, the algorithms and programs for realization of organizational procedures for certification of the professional training of operating personnel of aviation transport are developed. The indices, which determine the quality of special professional preparation, are also given. 2 ill. Bibl. 5. Russ.