Vol 62, No 3 (2019)

A design and manufacturing process for composite fittings (a part of a truss structure of aircraft) is discussed. Intersecting tubular rods are connected via ruled surfaces such as a hyperbolic paraboloid. A mathematical model of X-fitting surface is developed, and numerical simulation of the fitting is performed to optimize its geometry. Due to the thing that interface surface is ruled, reasonable composite application and, as a result, high weight efficiency of the structure may be achieved.

A complex mathematical model of the thermo-deformed state of a circular cylindrical shell reinforced by stringers for a vertically installed cryogenic tank during its filling was constructed. The model describes the local deviation of the shell generatrix due to the nonuniform temperature distribution and the action of an axial compressive load. Relations describing the temperature distribution along the shell and its radial displacement were obtained. The quantitative analysis of these relations was carried out. Estimations of the shell generating line deviation from the original rectilinear form, which can decrease the level of the critical axial loads and cause the shell buckling, are presented.

This paper proposes a numerical and experimental approach for determining the friction coefficient in gas turbine impeller dovetail joints. The approach involves comparing the results of numerical simulation of the impeller rotation at different friction coefficients and the experiment data from strain-gauge measurement of the structure characteristic areas.

A solution of initial attitude estimation is considered for the UAV with an inertial navigation system including a standard set of three-degree micro-electro-mechanical gyroscopic angular velocity sensors, accelerometers, and magnetometers.

A new analytical algorithm of modal control is developed for the sixth-order control system that represents the problem of descent module attitude stabilization using the values of two angles measured by free gyroscope and three components of angular velocity vector with respect to the corresponding coordinate axes measured by the angular velocity sensor. This algorithm belongs to the category of dynamic object control algorithms by the output vector and it is based on synthesis of a state vector observer.

The first-approach techniques for analytical evaluation of the airfoil shape and calculation of the aerodynamic coefficients for a box-wing aircraft are suggested. The reliability of the calculation results was estimated using FLZ code (the vortex lattice method). The comparison showed satisfactory convergence of coefficients for the clean configuration and some discrepancy for the take-off and landing configuration.

In this paper, rotors with artificial iced shapes are studied to develop insight in the potential of acoustics-based ice detection. Using the Helicopter Multi-Block CFD solver, approximate iced shapes are added to the blades and the results are analyzed using the FW-H method. Several candidate monitoring positions are assessed for acoustic sensors to be placed on the helicopter fuselage. The influence of ice on the aero-acoustic characteristics of a rotor is calculated, and parameters such as the ice amount and the icing position on the blade are quantified.

Complex variable function theory methods are used to study the jet propagation and prevention of jet reattachment to the nacelle during jet engine thrust reversal for reverser cascades with constant and variable blade angles. Results obtained are compared with experimental data.

The results of the probabilistic assessment of life for the low-pressure compressor rotor of the gas turbine engine for a regional aircraft are presented taking into account production tolerances. The calculation algorithm, preparation of the probabilistic model parameters, and the experimental program of automated probabilistic analysis are described, the example of the life calculation results is given.

A model of structural-geometric dimension calculation and integral characteristic estimation of the combustion chambers of the small-sized gas turbine engines at their conceptual design stage are developed.

As the result of ANSYS CFX calculation, a conclusion was drawn about the greater cooling effectiveness of vane platform with laidback fan-shaped perforation holes as compared with cooling effectiveness of vane platform with cylindrical holes.

The concept of a wave compressor using a centered isentropic wave for air compression is considered, and shock-wave structures are studied, which are arisen when a centered wave is focused. It is concluded that the characteristic centered compression wave with reflected weak discontinuity is optimal.

In this paper, the process of forming a flat blank is investigated, which allows the thickness variation along the part wall generatrix to be minimized.

The paper proposes an algorithm for electronic simulation of products made of composite materials and provides an example of using the developed algorithm.

Design concepts for wireless control system of large transformed net structure shape are discussed. Solutions of the problem of data communication via the optical channel for multiple receivers are discussed and proposed. The composite photoconverter with the feature of detecting a directed laser beam is described.

The adequate mathematical models are developed that allow investigating the thermoelastic stresses and strains arising in production of multilayer structures of spherical shape for aircraft. The method of finite integral transformations was applied to solve the model tasks stated.

The name of the second author of the article should be read as A.V. Tsipenko.