Vol 4, No 1-4 (2014)

The article proposes revised method of solving the contact problem for ring layer, taking into account frictional forces in the contact zone. The law of changes radial contact pressures is presented in the form of infinite series containing two groups of unknown constants. To determine unknown constants there was obtained the system of two functional equations.

The article offers the trigonometric probability distribution, and the method of sequences of numbers generating distributed on trigonometric law. Economic variables have a pronounced cyclicity so the distribution can be very useful in the analysis, research, planning, forecasting and modeling of the economic variables, objects and processes.

The article proposes a statistical theory of inelasticity of endochronic type, which takes into account initial microstresses and initial microdeformations, that are contained in the material. The theory main relations are formulated. The examples of the two-and one-element models were taken to provide calculations of hypothetical material uniaxial loading, which demonstrate the approach by assuming a uniform distribution of initial microdeformations. There is emphasized that in the process of loading the structural elements of the model can generate deformation of different signs that expands the boundaries of applicability of the theory.

The similarity parameters in the problem of flutter of a cylindrical shell were studied. As a mathematical theory of shells there was adopted a technical theory in mixed form. For a manometric pressure either formula of piston theory or formula of linearized potential flow theory is accepted. Physical conditions of modeling were derived from the equation of similarity parameters of the model and full-scale processes.

A known method of calculating the velocity of movement of constrained freeform solids under gravity is extended to cases of monomodal motion of gas bubbles and liquid droplets of arbitrary shape.

The results of application the axisymmetric rigid-plastic membrane finite element model to the study of forming a thin contour fixed metal plate under hydrostatic pressure are outlined. A comparison with the known numerical solutions and experimental data is provided.

The paper presents the results of experimental studies of the effective thermal conductivity of gas, water and oil-filled limestone samples under high pressures up to 400 MPa and temperatures in the range of 273-523 K. It is shown that the pressure leads to a nonlinear increase of the effective thermal conductivity of limestone and affects the nature of its temperature dependence.

The article examines the prediction of the residual life on the results of diagnosis of full-scale constructions with continuous monitoring of their technical condition.

In the paper the authors present a calculation of the characteristics of an airlift unit based on the methods of computational fluid dynamics (CFD). As a result of numerical simulation of unit operation its characteristics were received as well as the scalar distribution field of the gas phase. The basic methodologies for calculating airlift units such as Geyer method, a method developed in Donetsk National Technical University (DonNTU) and cfd-method are considered. A comparative analysis of the accuracy of these methods was conducted. It was shown that the results of calculations based on computational fluid dynamics and results obtained by the method of DonNTU are consistent with each other.