Issue 2

JTAM, Sofia, vol. 13 Issue 2 (1982)

Qualitative Geometric Parameters of Manipulation Systems Functional Capacities

L. Lilov, B. Bekiarov
IMB, Bulg. Acad. Sci., Bl 8 Geo Milev

The paper presents methods for the introduction of quantitative characteristics of the functional capabilities of manipulators. These methods, on one hand, make clear the genesis of the geometric evaluations, used at present and concerning the manipulator functional capabilities, while, on the other hand, they could serve as a basis for the generation of a limitless number of new evaluations, each of which could reflect a specific side of the manipulator action. The methods make possible any property of the manipulator, concerning the geometry of motion, to be formally defined and thus to be quantitatively evaluated. The geometric evaluations known are obtained as special cases and besides that it is introduced and discussed a number of new characteristics.

JTAM, Sofia, vol. 13 Issue 2 pp. 011-019 (1982), [Full Article]

Topologic Analysis of Bodies with Concentrated Masses

M. Konstantinov, V. Zamanov
High. Inst. Mech. Electr. Eng., Darvenica

The paper discusses the variety of dynamically equivalent models of bodies with masses concentrated in four points. Two of the mass points are situated on a given straight line. Considering two parameters, a thorough pattern of the variation of mass distribution and configuration is obtained. An algorithm for the calculation of such models is created and numerical results are given.

JTAM, Sofia, vol. 13 Issue 2 pp. 020-027 (1982)

Manoeuvre Coefficient of Manipulator Unit

B. Bekiarov, V. Hristov, P. Petrov
IBM, Bulg. Acad. Sci., BI 8 Geo Milev

The authors introduce "manoeuvre coefficient" which characterizes the manipulator capability to position the grip centre in different points, by means of various configurations. A universal programme system for visualizing an arbitrary scalar field is created. By means of that system it is solved the problem of visualizing the "manoeuvre coefficient" variation in the working region of a manipulator.

JTAM, Sofia, vol. 13 Issue 2 pp. 028-034 (1982)

A Note on the Non-Classical Heat Conduction

N. Petrov, N. Valchanov
IBM, Bulg. Acad. Sci., Bl 8 Cleo Milev

It is derived a generalized model of linear heat conductivity in non-deformable materials on the basis of the general theory of materials with fading memory. This model comprises a number of known models as special cases and makes possible the obtaining of new ones.

JTAM, Sofia, vol. 13 Issue 2 pp. 035-039 (1982), [Full Article]

On the Problem of Seismic Loading of Long-Base Structural Systems

S. Kisliakov
High. Inst. of Arch. and Civ. Eng., 1 Hr. Smirnensky Blvd. Sofia

A function, which takes into account non-simultaneous arrival of the seismic wave at different points of a long-base structure, is suggested in the paper. This function includes the three known so far basic cases as well as all intermediate ones.

JTAM, Sofia, vol. 13 Issue 2 pp. 040-041 (1982)

On the Ideas of Mass and Force in a Model of Continuum Media

N. Trendafilov
43 Buzludza Str., Sofia

The author proves that within the frame of Truesdell's and Noll's axioms, adding an extra supposition specific for the model treated, one could extend mass and force to measures. Then the Danford-Petis' theorem could be applied to both of them. This results in obtaining a presentation which is a generalization of the one known in the classic mechanics of continua, namely that force acting on a body is a sum of mass and surface forces.

JTAM, Sofia, vol. 13 Issue 2 pp. 042-045 (1982), [Full Article]

On Some Axisymmetric Two-Phase Flows

I. Zeleva
IMB, Bulg. Acad. Sci., Bl 8 Geo Milev

Equations, describing axisymmetric flow of a dispersive mixture which consits of viscous incompressible liquid and hard spherical particles, are discussed. It is determined the type of the system of differential equations in steady and unsteady case. A method, concerning flows of dilute suspensions and calculating the phase velocities, is determined. It is based on correctly stated problems of Cauchie for the system of equations of motion. A solution of the problem of dilute suspension flow in a straight cylindric tube of circular cross is obtained.

JTAM, Sofia, vol. 13 Issue 2 pp. 046-054 (1982)

Investigation of the Circulation Zone in Plane Turbulent Jet Cohesion to a Hard Wall

I. Antonov
High. Inst. of Mech. Electr. Eng., Darvenica

The circulation zone appearing in turbulent jet cohesion to a wall of arbitrary radius of curvature is investigated in the paper. The solution is obtained, using the equation of continuity and of momentum – the pressure distribution is experimentally given. Expressions for the circulation flow, the line dividing the straight and the reverse current and the maximum velocity of the latter are obtained. It is made a comparison between the results and experimental data for a definite case of outflow.

JTAM, Sofia, vol. 13 Issue 2 pp. 055-064 (1982)

An Investigation of the Spacious Inhomogeneity of a Dependent Discharge

G. Gadiak, V. Sveigert
630090, Novosibirsk 90, ITPT

The paper dicusses the inhomogeneity of one-dimensional dependent gas discharge excitated by a relativistic shaft of electrons. The kinetic equation of the shaft of electrons is solved using Monte Carlo methods. It is shown that the inhomogeneity of the gas ionization is determined by the values of the dimensionless parameters d/R(U*) , UR(U*)/(U*d) and by the anode material. A relation for the optimal value d/R(U*) which ensures the best homogeneity of the ionization is determined, taking into account UR(U*)/(U*d). It concerns steel anode.

JTAM, Sofia, vol. 13 Issue 2 pp. 065-072 (1982)

A Method for the Investigation of the Microstresses in Strain Rate Sensitive Plastic Materials

A. Baltov, N. Bontcheva, R. Kazandjiev, Iv. Radovanov, St. Vodenitcharov
IBM, Bulg. Acad. Sci., Bl 8 Geo Milev

Method for the microstress investigation, using two-dimensional experiments and X-ray difractometry, is given. A model, proposed by the first two authors, is taken as a basis. This method is applied to the investigation of steel, produced in Bulgaria.

JTAM, Sofia, vol. 13 Issue 2 pp. 073-091 (1982)

A Method for Pressed Rheonomic Bar Calculation

K. Popov1, G. Mandicev2, K. Hadzov2
1High. Inst. Chem. Techn.
2High. Inst. of Mech. Electr. Eng., Darvenica

It is derived an expression for the calculation of pressed rheonomic bars. The expression is based on a stability criterion obtained by the authors. A formula, calculating the bar necessary slenderness, is obtained, taking into account the bar life and the loading given. An expression is derived which calculates the slenderness according to Gerard's criterion. A comparison between the two expressions is made. The expression for the bar calculation, proposed by the authors, could lead to material saving.

JTAM, Sofia, vol. 13 Issue 2 pp. 092-095 (1982)

A Method for the Integration of the Equations of the Theory of Elasticity in Plane Case

D. Kolarov
Inst. Mech. Biomech., Bulg. Acad. Sci., Bl 8 Geo Milev

It is proposed a method for the integration of a system of partial differential equations referred to problems of plane stress and strain state of bodies. The method allows solving problems of complex and mixed boundary conditions in tractions and displacements. The calculations could be very conveniently and easily performed on a computer.

JTAM, Sofia, vol. 13 Issue 2 pp. 096-100 (1982)

Integration of the Equations of the Three-Dimensional Boundary Value Problem in the Theory of Elasticity

D. Kolarov
Inst. Mech. Biomech., Bulg. Acad. Sci., Bl 8 Geo Milev

The method for the integration of partial differential equations of the theory of elasticity developed by the author, is applied to the determination of displacements, stresses and strains in three-dimensional bodies. The boundary value problem is solved for complex loadings and supports on the body surface.

JTAM, Sofia, vol. 13 Issue 2 pp. 101- (1982)