Vol 10, No 2 (2011)

Let’s consider the method allowing to solve the problem of rational distribution of Tsiolkovsky’s numbers in stages and define the appropriate mass-power proportions for the parametric range of launch vehicle modifications where the stages are shaped from the universal rocket units. The problem solution converges to the general task of non-linear programming. The method is described for a version of a two-stage launch vehicle. But it can be easily applied to the versions with a great number of stages.

The paper presents the results of seal tightness calculation during different operation modes in an aircraft engine. The assessment of tightness is carried out along with the calculation of seal ring deformations and identifying the unit vibrating condition.

The results obtained during the investigation of the shape memory effect in NiTi alloys have been applied in practical designs of the aerodynamic surface deployment unit of a guided missile. The subjects under discussion are estimation of the efficiency of the developed unit, operating conditions, and analysis of successful application of components made of materials with the shape memory effect in newly developed units of the latest aircraft.

Problems of flight-navigation complex diagnostic analysis are discussed. Methods of complex morphology description based on graph and tensor theories are suggested. These methods make it possible to simplify the algorithm for the creation of a set of diagnosable parameters on the basis of physical and analytical division into circuits, nodal pairs and open chains. The state evaluation is implemented on the basis of a “compound-tensor” which includes all parameters of separate elements.

The paper deals with the solution of the Earth remote sensing problem by a cluster of ordinary nanosatellites combined in a network and distributed over the inter-turn interval of the orbit. The number of nanosatellites in a cluster used to perform global observations for 24 hours can be determined by statistical modeling on square matrices, taking into account uncontrollable and random position of such satellites in a cluster. Another statistical phenomenon is investigated along with the percolation threshold, namely, the point of maximum clusterization possessing robustness.

The problem of minimizing drag of symmetric airfoil at the given area and chord is dealt with. Optimization is obtained by the adjoint gradient method for an incompressible viscous flow. The primal problem is solved by the SIMPLE algorithm using the Star-CD software. Adjoint equations are solved by the SIMPLE adapted algorithm.

The paper deals with the problem of optimal correction of quasielliptical and circular orbits with limited thrust engines in the Earth central gravitational field with the use of spacecraft motion model for Laplace vector components. The control structure on the turn is justified the motion equations are averaged and their accuracy is assessed. The influence of the level of acceleration caused by thrust on the optimal control structure is investigated.

The high-level performance constant volume valve combustion chamber is intended for advanced power generating engine systems with a pulsating work process. The review of both published basic results obtained during the investigations and the new ones with recommendations for further chamber improvement is presented. The chamber can be applied in pulse jet engines, as initiator of detonation in detonation engines, as well as in gas-dynamic lasers and MHD generators.

The article deals with measurement techniques and methods of their optimization using the provisions of the probability theory and mathematical statistics. Dependence of measurement techniques on technological heredity is investigated.

The paper presents the research of crystallographic orientation formation during the rolling of sheets from aluminum alloy 8011A and the influence of such orientations on anisotropy and earing. The main orientations in this alloy are the cubic {001}<100>, nearcubic {210}<001> textures, the rolling {112}<111> and S-{123}<634> textures and the orientation {011}<112>. The paper shows that changes in the rolling and heat treatment modes lead to different combinations of the mentioned grain orientations and consequently to variant anisotropic properties. The new technological parameters of 8011A sheet production have been developed to eliminate earing during drawing.

The blade wave finite element has been developed. A FORTRAN code program has been developed for the modal analysis of rotating nonuniform heated blades of gas turbine engines. Natural modes of oscillation of two compressor blades have been analysed.

The paper deals with the process of transformation of longitudinal deformation wave at the boundary of heterogeneous bars with a linear elastic element. The procedure of numerical computation of deformation wave transformation process in a bar system is presented. The results of modeling are compared with the analytical solution for a test problem.

The possibility of using prototypes produced by laser stereolithography as parts of small-sized turbodrives is analysed. Both calculation analysis using the finite element method and an experimental one – on a special test-bed-have been carried out. As a result, the possibility of using such prototypes in turbodrives with the rotor speed limitation up to the level at which equivalent stresses in the parts do not exceed 40 MPa was established.

The scalar diffractive theory (in paraxial and non-paraxial cases) has been used for the investigation of focal domain for lens+axicon and lens+logarithmic axicon optical systems. It was shown that focal domain has a peak with a subwavelegth feature size. The use of this peak with shifting of the remaining part of the focal domain into the substrate makes it possible to improve the resolution for applications of multiphoton polymerization.

The paper deals with the possibility of producing a dynamic positioning system for manned submersibles over the service object. The dynamic positioning system is a part of the navigation system for a manned submersible.

A mathematical model of optical radiation interaction with skin tissues is constructed, which takes into account the effects of stimulated Raman scattering. On the basis of numerical experiments the features in the Raman scattering spectra are revealed to characterize skin abnormalities. The possibility of significant increase in information content for optical coherence tomography and Raman spectroscopy joint usage is shown. Recent improvement is achieved by significantly reducing the volume of diagnostic measurements during the tissue layers isolation with the help of OCT, followed by their analysis by Raman spectroscopy. Differences in Raman scattering intensities for abnormal and normal tissue layers are established, their values may differ by an amount of 40%.

The paper is devoted to the development of kernels for texture images. We suggest using integral probability metrics as a similarity measure of texture images on which the kernels proposed are based. The kernels have been analysed using the method of discriminant analysis and the support vector method for test image sets.

An approach to solving the problem of the on-board algorithm specification is proposed. This approach is founded on the calculus of a realtime control algorithm. The possibility of the automation of syntax reduction for the specification is also considered.

The paper describes the automation of design and technological preparation of production, identifying problems and solving them. The resulting mathematical model eliminates the conflict between design and technological departments.