Effect of heating on the dynamic behavior of a shell with partially damaged thermal insulation

The influence of aerodynamic heating of the aircraft skin with a partially damaged thermal insulation on its dynamic behavior is studied numerically. The study is carried out in two steps: the first step is to determine the temperature field in the shell; the second step is to measure the values of structure material characteristics depending on its temperature, to correct the stiffness matrix of the skin, and to solve the dynamics problem. The examples are considered.     

A technique of computer-aided synthesizing a finite element model of wing center section and outer wing torsion box joint for a transport aircraft

A technique of synthesizing the finite element model of the flange joint of the outer wing torsion box with the wing center section for a transport aircraft is presented. The technique is based on the functional decomposition principle, in which the general model of wing torsion box is synthesized from the separate substructure models including the flange joint. It has been shown that the manual input is significantly reduced, when the computer-aided synthesis is applied. This made it possible to cut time of synthesis and decrease the probability of error occurrence.     

A technique of design analysis for the gas turbine engine regenerator with complanar channels according to the heat flow and hydraulic resistance

A technique is presented for design analyzing a regenerative plate heat exchanger with complanar channels. Also derived is the formula for optimum relationship of flow areas for gas and air branching channels.     

Analysis of stresses in a cylindrical shell under transverse local loading

The solution is obtained based on the differential equations for the general theory of shells and approximate equations that are the components of the method of asymptotic synthesis. Numerical results are presented.     

Analysis of a coaxial gas ejector

In this paper, the results of investigating a coaxial gas ejector without increase of passive flow pressure are presented. A technique for calculation of coaxial ejectors has been developed. This investigation has resulted in the optimal structure of ejector with a high value of ejection coefficient.     

A synthetic aviation hydraulic fluid of new generation

The results of investigating a domestic synthetic hydraulic fluid of new generation are presented. By comparing with the existing domestic and foreign analogues, we specify the main advantages and disadvantages of this hydraulic fluid.     

Analysis of Fast Variations in Electron Fluxes in the Gap Region Using the Normalized Range Method Based on Measurement Data on the SiriusSat-1 Satellite

Cosmic Research - The use of the normalized range method for an analysis of the fast variability of electron fluxes in near-Earth space is proposed. This method makes it possible to conclude...     

A priori zenith wet delays in the analysis of VLBI CONT sessions

Tropospheric delay is one of the major sources of error in VLBI (Very Long Baseline Interferometry) analysis. The principal component of this error can be accurately computed through reliable surface pressure data —hydrostatic delay— yet there is also a small but volatile component —wet delay— which is difficult to be modelled a priori. In VLBI analysis, troposphere delay is typically modelled in the theoretical delays using Zenith Hydrostatic Delays (ZHD) and a dry mapping function. Zenith Wet Delay (ZWD) is not modelled but estimated in the analysis process. This work studies inter alia the impact of including external GNSS estimates to model a priori ZWD in VLBI analysis, as well as other models of a priori ZWD.In a first stage, two different sources of GNSS troposphere products are compared to VLBI troposphere estimates in a period of 5 years. The solution with the best agreement to VLBI results is injected in the VLBI analysis as a priori ZWD value and is compared to other options to model a priori ZWD. The dataset used for this empirical analysis consists of the six CONT campaigns.It has been found that modelling a priori ZWD has no significant impact either on baseline length and coordinates repeatabilities. Nevertheless, modelling a priori ZWD can change the magnitude of the estimated coordinates a few millimeters in the up component with respect to the non-modelling approach. In addition, the influence of a priori ZWD on Earth Orientation Parameters (EOP) and troposphere estimates —Zenith Total Delays (ZTD) and gradients—has also been analysed, resulting in a small but significant impact on both geodetic products.     

Nonlinear filtering for sequential spacecraft attitude estimation with real data: Cubature Kalman Filter,Unscented Kalman Filter and Extended Kalman Filter

This article compares the attitude estimated by nonlinear estimator Cubature Kalman Filter with results obtained by the Extended Kalman Filter and Unscented Kalman Filter. Currently these estimators are the subject of great interest in attitude estimation problems, however, mostly the Extended Kalman Filter has been applied to real problems of this nature. In order to evaluate the behavior of the Extended Kalman Filter, Unscented Kalman Filter and Cubature Kalman Filter algorithms when submitted to realistic situations, this paper uses real data of sensors on-board the CBERS-2 remote sensing satellite (China Brazil Earth Resources Satellite). It is observed that, for the case studied in this article, the filters are very competitive and present advantages and disadvantages that should be dealt with according to the requirements of the problem.