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CONTENTS
Volume 9, Number 6, November 2022
 


Abstract
The study presents the results of the research of heat and heat exchange processes on the heat-stressed elements of the structure of an advanced TsAGI descent vehicle. The studies were carried out using a mathematical model based on solving discrete analogs of continuum mechanics equations. Conclusions were drawn about the correctness of the model and the dependence of the intensity of heat and mass transfer processes on the most heatstressed sections of the apparatus surface on its geometry and the catalytic activity of the surface.

Key Words
descent aircraft; gas dynamics; heat and mass transfer; mathematical modeling; multicomponent flow

Address
Oleg A. Pashkov and Boris A. Garibyan: Moscow Aviation Institute (National Research University), Moscow, Russia

Abstract
This study is aimed to accurately predict the vibration response of two types of functionally graded sandwich plates, one with FGM core and another with FGM face sheets. The gradation in FGM layer is quantified by exponential method. An efficient zig-zag theory is used and the zigzag impacts are established via a linear unit Heaviside step function. The present theory fulfills interlaminar transverse stress continuity at the interface and zero condition at the top and bottom surfaces of the plate for transverse shear stresses. Nine-noded C-0 FE having 8DOF/node is utilized throughout analysis. The present model is free from the obligation of any penalty function or post-processing technique and hence is computationally efficient. Numerical results have been presented on the free vibration behavior of sandwich FGM for different end conditions, lamination schemes and layer orientations. The applicability of present model is confirmed by comparing with published results. Several new results are also specified, which will serve as the benchmark for future studies.

Key Words
finite element analysis; functionally graded material; sandwich plates; zig zag theory

Address
Simmi Gupta and H.D. Chalak: Department of Civil Engineering, National Institute of Technology, Kurukshetra, Haryana 136-119, India

Abstract
The current state of telecommunications infrastructure in the Arctic does not allow providing a wide range of required services for people, businesses and other categories, which necessitates the use of non-traditional approaches to its organization. The paper proposes an innovative approach to building a combined communication network based on tethered high-altitude platform station (HAPS) located at an altitude of 1-7 km and connected via radio channels with terrestrial and satellite communication networks. Network configuration and composition of telecommunication equipment placed on HAPS and located on the terrestrial and satellite segment of the network was justified. The availability of modern equipment and the distributed structure of such an integrated network will allow, unlike existing networks (Iridium, Gonets, etc.), to organize personal mobile communications, data transmission and broadband Internet up to 100 Mbps access for mobile and fixed subscribers, rapid transmission of information from Internet of Things (IoT) sensors and unmanned aerial vehicles (UAV). A substantiation of the possibility of achieving high network capacity in various paths is presented: inter-platform radio links, subscriber radio links, HAPS feeder lines - terrestrial network gateway, HAPS radio links - satellite retransmitter (SR), etc. The economic efficiency of the proposed solution is assessed.

Key Words
gateway; high altitude platform station (HAPS); low earth orbit (LEO); radio channel; radioisotope power system (RPS); unmanned aerial vehicle (UAV)

Address
Gennady V. Chechin, Valentin E. Kolesnichenko and Anton I. Selin: Moscow Aviation Institute (National Research University), 125993 Volokolamskoe highway 4, Moscow, Russian Federation

Abstract
The rapid decrease of fossil fuel resources and increase of environmental pollution caused by aviation industries have become a severe issue which leads to an increase in the greenhouse effect. The use of biofuel becomes an option to alleviate issues related to unrenewable resources. This study presents a computational simulation of the biofuel combustion characteristics of various alternative fuels in an annular combustion chamber designed for training aircraft. The biofuels used in this study are Sorghum Oil Methyl Ester (SOME), Spirulina Platensis Algae (SPA) and Camelina Hydrotreated Esters and Fatty Acids (CHEFA). Meanwhile, Jet-A is used as a baseline fuel. The fuel properties and combustion characteristics are being investigated and analysed. The results are presented in terms of temperature and pressure profiles in addition to the formation of NOx and soot generated from the combustion chamber. Results obtained show that CHEFA fuel is the most recommended biofuel among all four tested fuels as it is being found that it burns with 37.6% lower temperature, 15.2% lower pressure, 89.5% lower NOx emission and 8.1% lower soot emission compared with the baseline fuel in same combustion chamber geometry with same initial parameters.

Key Words
annular chamber; biofuels; CFD simulation; emissions; NOx; soot

Address
Joanne Zi Fen Lim and Nurul Musfirah Mazlan: School of Aerospace Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia

Abstract
In this article, we propose a criterion for ensuring the asymptotic stability of large multiple delays, based on the direct Lyapunov method. Based on this criterion and distributed control scheme, the controllers are synthesized by the PDC to stabilize these large-scale systems with multiple delays. And we focus on the results which shows the high effective by the proposed theory utilized for damage propagation for aircraft structural analysis of composite materials. Finally, the numerical simulations confirmed the effectiveness of the method.

Key Words
aerospace vehicles; LMI; nonlinear systems; smart control; stability analysis

Address
C.C. Hung: Department of Mechanical Engineering, National Taiwan University, Taiwan; Faculty of National Hsin Hua Senior High School, Tainan, Taiwan
T. Nguyễn: Ha Tinh University, Dai Nai Campus, No. 447, Street 26/3, Dai Nai Ward, Ha Tinh City, Vietnam


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