Vol 10, No 6 (2011)

The paper presents a mathematical model of motion of an upper-stage rocket with a toroidal tank filled with liquid fuel around the centre of mass. Time dependencies of motion parameters are established using a numerical and an analytical method. Limiting cases of orientation in Eulerian angles are analyzed.

Experimental studies to define the reflection characteristics of aircraft surfaces have been carried out. The behavior of the reflectance under pulse periodic action with different values of intensity has been analysed. A test-bed for laser detection and ranging of objects is used to analyse the influence of sounding laser radiation parameters on the probability of detection and recognition. Relationships between the image contrast range and the impulse angle of incidence, wavelength and relative pulse duration have been obtained. Experimental estimation of the influence of the radiation wavelength on the probability of detecting objects in case of using lasers has been carried out.

The paper deals with the problem of developing problem-oriented systems for automated solution of space vehicle design tasks. The paper presents an algorithm for testing the tasks for correctness and a method of defining the sequence of performing calculations, subsequently obtaining the numerical values of the required parameters for the space vehicle airborne systems. The problem of obtaining numerical values of mass and dimensional characteristics of the space vehicle as a whole is discussed. The software developed in the DELPHI XE environment for solving the tasks set is described. The possibility of integrating the problem-oriented system with a system of product data management (PDM-system) is analysed.

The paper presents the results of the calculation of noisiness of a four-point bearing depending on the accuracy of producing as a part of the product in which it works. The calculation was performed according to the methods and programs developed by the authors. The noisiness of the separator and the balls that exists when the bearing is placed in any kind of an elastic system is calculated. Natural frequencies of bearing elements are defined with a given load on it as applied to the vibration set. It is shown that the errors of bearing production result in parametric excitation of elastic systems and excite oscillations with natural frequencies in them which produce the greater part of noisiness both of the systems and the bearings.

The article is devoted to a new algorithm for solving complex constrained multiobjective optimization tasks on the basis of probability-based GA. An efficient modification of the algorithm using adaptive mutation and Pareto set prediction is proposed. The results of efficiency investigation are presented.

A new method of nondestructive quality control of mechanical-rubber goods vulcanization is suggested. The method is based on the measurement of rubber electric resistance to direct and alternating current during vulcanization

The paper presents a method of modeling up-to-date hydraulic complexes on the basis of using the theory of dynamic analogies. An algorithm of modeling the state of a hydraulic system on the basis of working fluid parameters is described.

The paper deals with ways of determining stress during numerical simulation of metal forming processes. A mathematical model of anisotropic elastic-plastic material and an algorithm for the computation of stress-strain state using this model have been developed.

The experiment center and the steps of varying the factors of the experimental design to test ultralow power turbines (ULPT) centripetal (CPULPT), axial (AULPT) and centrifugal (CFULPT) types are defined. The rational ranges of varying these factors in terms of rotatable orthogonal central composition plan (ROCCP) feasibility, as well as the values that take factors at the appropriate levels of variation are also defined.

The paper presents the results of the calculation of noisiness of a four-point bearing depending on the accuracy of producing as a part of the product in which it works. The calculation was performed according to the methods developed by the authors. The results of calculating the noisiness of the outer ring show good agreement with the experimental data obtained in the course of tests at the vibroacoustic laboratory of the factory. The noisiness of the separator and the balls existing when the bearing is placed in any kind of an elastic system is calculated.

A mathematical model of the venting heat-insulated instrument bay of the photographic reconnaissance plane thermal state is developed. Direct and inverse problems of heat exchange are solved, confidence intervals of estimated parameters are determined.

A procedure making it possible determine to the law of motion of falling parts of a high-speed hammer in the form of Fourier series for nonperiodic function is developed. The regularities derived allow calculating the speed and acceleration at any point of metal flow during forging.

The paper deals with starting a spark-ignition gas fuel internal combustion engine with an electronic control system. The influence of the engine temperature on the gas supply characteristics during starting and warming up is shown. The basics and peculiarities of the algorithm of starting a gas fuel internal combustion engine with an electronic control system are described.

The paper presents a new method to control the reliability of conversion based on the formation of a difference signal of the converter being verified and the reference converter. The principles of producing reliability control devices on its basis are also discussed. It is shown that in all cases the reliability control error is determined by the weight of the least significant digit of the reference digital angle converter. The relation between the permissible control error, the reliability of the reference digital angle converter and the ratio of the number of digits of the reference converter and the one being verified is established.

A geometric model of a pipeline has been developed for use in automated design of fuel systems. The mathematical description is based on the use of R-function apparatus. The functions that describe the pipeline geometry include a number of parameters which make it possible to change not only the form of the shaft but also that of the section (while retaining its area).

The article presents a model of a hybrid fuzzy neural classifier with a built-in prediction function of pilot's erroneous actions. The analysis of the network constructed is performed using real and test samples.

The problem of specifying time characteristics of distributed processes competing for a program resource is solved and a method of finding the optimum number of processors providing directive time of performing set volumes of calculations is suggested.

A dynamic model of multichannel queueing system with non-stationary streams, waiting in a limited-length queue and partial mutual assistance of channels expressed in the opportunity of simultaneous service of a customer by two channels is described. Expressions for the basic probability-time characteristics of the system are given. The results of modeling the functioning of a hub airport as an example of the system discussed are described.

Discrete event simulation method is used to research load balancing algorithms in a program. Traffic transmission processes in computing networks are simulated with Petri nets. The program is changed to apply this method.