bluuebunny/crossref_metadata_2025 huggingface dataset:
Creep strength and microstructure of a modified P911-type steel weld joint
Authors: Tkachev E , Belyakov A
Published: January 2021

The creep strength and microstructure of the weld joint of the modified P911-type steel has been studied. The creep rupture time of the welded joint at 650° of 1375 h is close to that of the base metal. The heat affected zone-is found to be the weakest area due to the increased size and relatively high coarsening rate of precipitates. The increased boron content in the weld steel effectively stabilizes the M23(C,B)6 particles and is beneficial for the creep strength of the weld joint in the fusion zone.
Structure and corrosion properties of stainless steel after high-power ion beam processing
Authors: Zhidkov M V , Gazizova M Y , Ligachev A E , Pavlov S K , Remnev G E
Published: January 2021

In this study, the surfaces of AISI 321 stainless steel samples were irradiated with one shot of a high-power ion beam (HPIB) at pulse energy densities of 1 and 3 J/cm2. The surface morphology and structural-phase state in the near-surface layers of the treated samples were analyzed using scanning electron microscopy and electron backscatter diffraction. Additionally, the influence of HPIB processing on the resistance to intergranular corrosion was investigated using electrochemical experiments.
New high-entropy oxide phases with the magnetoplumbite structure
Authors: Zhivulin V E , Trofimov E A , Starikov A Yu , Gudkova S A , Punda A Yu , Zherebtsov D A , Zaitseva O V , Vinnik D A
Published: January 2021

In the studied BaO–SrO–CaO–La2O3–Fe2O3–TiO2–Al2O3–Mn2O3–CoO–In2O3–Ga2O3–Cr2O3 system there were synthesized three new high-entropy magnetoplumbite phases by solid-state sintering in air at 1300, 1350, and 1400 °C.

The average composition of the high-entropy phases obtained at 1350 °C can be described by the formulas:

Ba0.48Sr0.30Ca0.05La0.15Fe1.62Ti1.78Al1.55Mn1.45Co1.11In1.29Ga1.52Cr1.71O19;

Ba0.39Sr0.37Ca0.05La0.18Fe2.88Ti1.60Al1.69Mn1.09Co0.92In1.20Ga1.27Cr1.38O19;

Ba0.37Sr0.29Ca0.05La0.28Fe5.85Ti1.15Al0.97Mn0.74Co0.56In0.85Ga0.94Cr0.97O19.

The data obtained indicate that a significant portion of calcium was not incorporated into the high-entropy phase. This must be taken into account in the course of subsequent experimental work on the creation of homogeneous phases necessary for the study of their electrical and magnetic properties.
Stack fabric felting to get PCM GIIc improvement and LVI tolerance
Authors: Forental G A , Kheruvimov A V , Nikonov A V , Sapozhnikov S B
Published: January 2021

In this work, there was developed a three-axis CNC felting machine with one barbed needle. Felting is a kind of needle-punch technology for joining fabric stack by broken and pulled fibres. The density of needle hits is a valuable factor to make the required shear strength of polymeric composite materials in the specified places. Using the glass-fibre reinforced plastic (GFRP) with plain weave felted fabric, a noticeable decrease in strength with an increase in the needle hits density from 0 to 90 cm−2 is shown. For a laminated GFRP made from a stack of fabrics, it has been shown that the shear strength of the single-lap joint and the interlaminar shear fracture toughness GIIC significantly increase with an increase in the needle hits density. This is important for modern aircraft shells exposed to random low-velocity impacts during ground or flight operations.
Meshfree Methods of Airframe Stress Analysis
Authors: Kalutskiy N S
Published: January 2021

Present-day meshfree methods of numerical computer analysis of structures have been analyzed in this article. Principal mathematical ratios used in meshfree methods have been provided. Building of a shape function, one of the principal problems of the meshfree method, has been discussed, and an algorithm for the building of a shape function by using polynomial basis functions has been proposed. The algorithm developed has been tested on solving an elementary problem. The Conclusion section of this article contains solution results of a practically important problem of mechanical stress concentrations in a typical aircraft stringer. Comparative analysis of the accuracy of the results obtained by the conventional FEM and the meshfree method proposed has been conducted.
Recycling of Critical Raw Materials from Hydrogen Chemical Storage Stacks (PEMWE), Membrane Electrode Assemblies (MEA) and Electrocatalysts
Authors: Moschovi A M , Zagoraiou E , Polyzou E , Yakoumis I
Published: January 2021

The increase in energy demands for the establishment of a modern digital era has resulted in the significant limitation of the energy sources. The depletion of energy reserves drew attention to alterative renewable energy sources that can satisfy the energy requirements in an environmentally friendly way. Hydrogen is an ideal chemical energy storage. Proton exchange membrane water electrolysis (PEMWE) is a promising technology as a green source of high-purity hydrogen. For that reason, PEMWE devices are already used in aerospace to produce oxygen for the crew on the Space Stations. The use of Critical Raw Materials (CRMs, especially Pt and Ir) and high cost materials in the PEMWE systems compromises their economic feasibility. It is necessary to implement End-of-Life (EoL) strategies that optimise the recovery of CRMs within feasible and environmentally friendly processes. In this paper an overview of the existing technologies for recycling of Membrane Electrode Assembles and electrocatalysts from PEMWE systems are revealed. MONOLITHOS has developed a novel optimized hydrometallurgical method for high PGMs recovery from spent automotive catalysts. This work aims to describe how this method can be applied to the EoL phase of PEMWE to improve techno-environmental and techno-economical performance of CRMs recovery.
Conceptual design and parametric structural modeling of a FWAV biomimetic flapping wing
Authors: Rayhan Saiaf Bin
Published: January 2021

Flapping wing air vehicle is the latest technological achievement of the aviation industry, which is still maturing as a miniature of large aircraft before finally achieving the finest development. By mimicking the nature, parametric structural modeling of a flapping wing, made of composite membrane and aluminum alloy support beam is numerically investigated adopting commercial FE code Ansys. A flapping cycle is divided into twelve segments, and for each segment, the maximum stress, first ply failure and the deformation are studied. It is found that the fiber orientation angle has the highest impact on the structural properties during a flapping cycle, where improper stacking sequence will cause failure to the wing. Moreover, increasing the ply thickness has a positive impact on the overall structural performance of the model. Finally, appropriate support beam orientation can further improve the structure by increasing the stiffness and reducing the maximum stress significantly without increasing the overall weight of the wing.
On Unsteady Flow Analysis of a Round Spike Blunt Nose Afterbody in Mach 6 Flow
Authors: Vashishtha A , Khurana S
Published: January 2021

An aerospike, in front of a blunt body, has largely been deemed as a key passive control device for effectively reducing the wave drag and aerodynamic heating associated with high-speed flows. In addition, it has been reported that the presence of a spike brings in unsteadiness in the form of oscillation and pulsation to the flow characteristics. Past researchers, having investigated mainly the aerothermodynamic coefficients, have hinted towards the suppressing of such oscillations with the use of a round nose spike over a sharp spike, though a thorough and a concrete result is yet to be established together with offering a detailed explanation of the flow physics and its dependence on the spike’s geometric characteristics (spike-length to afterbody-diameter ratio, L/D). Numerical investigation has been carried out using axisymmetric Navier-Stokes laminar flow solver at hypersonic Mach number of 6.0. A round-tip spike with a flat face cylindrical afterbody have been simulated for spike length ratios of L/D = 0.5 – 2.0, with spike diameter to-afterbody diameter (d/D) of 0.1. The behavior and subsequent control of flow pulsation for a round (hemispherical) spike with varying L/D-ratio has been established.
Aeroelastic optimisation of manufacturable tow-steered composite wings with cruise shape constraint and gust loads
Authors: Wang Zhijun , Peeters Daniël , Roel De Breuker
Published: January 2021

In the structural design of aircraft wings, aeroelastic tailoring is used to control the aeroelastic deformation to improve the aerostructural performance by making use of directional stiffness. Recently, tow-steered composites, where the fibre angles continuously vary within each ply, have been proven to have the potential to further expand the advantages of aeroelastic tailoring. This work extends TU Delft aeroelastic tailoring framework PROTEUS by introducing a lay-up retrieval step, so that it can be used for the conceptual design of tow-steered composite wing structures. In the extended framework, aeroelastic tailoring and lay-up retrieval are sequentially and iteratively performed to take static and dynamic loads, manufacturing and cruise shape constraints into consideration. The first step is carried out using PROTEUS, in which the lamination parameters and thickness of the wing sections are optimised under manoeuvre and gust load conditions. Further, for ensuring optimal aircraft performance in cruise flight conditions, the jig twist distribution is allowed to be optimised to maintain a desired prescribed cruise shape. In the second step, the stacking sequence, including minimum steering radius constraint, is retrieved. Since the lamination parameters cannot be matched exactly during the retrieval step, the constraints are checked, and tightened to take the performance loss during retrieval into account. The first step is repeated until all constraints are satisfied after fibre angle retrieval. To demonstrate the usefulness of the proposed optimisation framework, it is applied to the design of the NASA Common Research Model (CRM) wing, of which the objective is minimizing wing mass subjected to aerostructural design constraints, such as aeroelastic stability, aileron effectiveness, material strength and buckling load.
Repair & maintenance by Metal Additive Manufacturing process on Titanium alloy parts
Authors: Lhabitant Solène , Badouaille Florimont , Remache Djamel , Cohen Guillaume , Toufine Alain
Published: January 2021

The CRO2
project* deals with both the aircrafts’ parts repair & maintenance and the Additive Manufacturing by metal powder Directed Energy Deposition **.

Repairing parts in the aerospace industry is a potential application for additive manufacturing technologies. It’s thus possible to reduce operating losses and to avoid waste of costly and strategic raw materials. CRO2 proposes a pre-industrial development to rebuild lost shapes and functions of Ti64 alloys structures as example in air bled piping. Laser Metal Deposition (DED) process was used for Ti64 parts manufacturing. Tensile and fatigue tests were performed on several samples to characterize the AM material. The mechanical properties of the tested samples are comparable to those of the laminate Ti64 and their microstructure is typical of additive manufacturing. The reliability of the proposed technique, compared to welding repairs’ process, has been successfully demonstrated using aircraft environmental qualification tests at high temperature and pressure carried out on thin representative pipings.

(*) CRO2: Cost Repair Overhaul Optimization

(**) DED AM: Directed Energy Deposition Additive Manufacturing
SPARE project – improvement of continuous compression moulding process for the production of thermoplastic composite beams
Authors: Angiuli Riccaro , Dell’Anno Federica , Cosma Leonardo , Raganato Umberto , Passaro Alessandra
Published: January 2021

In recent years, thermoplastic matrix composites have seen an increasing interest from the research and development sector due to the versatility of use and the wide potential in sectors such as automotive, aeronautics and transport. Furthermore, the thermoplastic matrix allows the use of simpler, faster and automatable production cycles and joining systems. As part of the SPARE project, the continuous compression moulding process (CCM) was upgraded using as numerical simulation, monitoring via infrared thermography and induction welding. Thanks to these innovations, the CCM process can ensure savings in terms of production costs, reduction of waste and a higher level of automation, the proposed work will illustrate the activities carried out during the project. The numerical simulation was used to analyze the heating process and verify its uniformity in order to identify the best configuration to obtain uniform heating, infrared thermography, on the other hand, was used to continuously monitor the temperate of the laminate at the entrance and exit of the compaction zone and to measure the process temperature and the degree of uniformity.

Finally, at the end of the production process, a tool was developed for the induction welding of the laminates for the construction of complex beams with a T or H cross section.
Virtual testing activities for the development of a hybrid thermoplastic composite material for the NHYTE project
Authors: Dotoli Rosario , Gerardi Antonio , Polydoropoulou Panagiota , Lampeas George , Pantelakis Spiros , Carpio Rovira Alfonso
Published: January 2021

Designing composite structures with a good level of confidence and accuracy requires access to allowables values. The allowables generation is extremely time and cost consuming. In fact, various layups, experimental tests and environmental conditions have to be taken into account for each material to be characterized. Moreover, each test configuration needs many repetitions to obtain a statistical evaluation of the mechanical property. A robust alternative to reduce the experimental time and costs is the use of virtual allowables calculated and predicted thanks to advanced multiscale simulations. This paper deals with the activities of virtual testing carried out in the European NHYTE Project for the development and characterization of a hybrid thermoplastic composite material for the aerospace sector. The main aim has been to reduce tests and risk associated with the use of the hybrid composite in aerospace structures. This can be achieved by lowering the probability of failure of primary structures through the use of A-basis or B-basis strength allowables as design values. For this purpose, coupons of the hybrid thermoplastic composite have been accurately analysed using virtual tests. Starting from a micromechanics approach and taking into account the different constituents (PEEK matrix, PEI films and fibre reinforcement), a material model has been implemented; then it has been propagated to different scales until the element level. For virtual testing to be useful in the certification process, this numerical model has been validated by a synergic approach, correlating the simulation results with the experimental data carried out by Applus+ Laboratory. At the end, it has been possible to demonstrate that the resulting models are an excellent tool to speed up the certification process for complex structures, as required in the Aeronautical industry.
Advanced Acoustic Emission Source Location in Aircraft Structural Testing
Authors: Grigg S , Featherston C A , Pearson M , Pullin R
Published: January 2021

Acoustic emission (AE) is an in situ Structural Health Monitoring (SHM) technique, where a structure is monitored for the ultrasonic waves produced due to crack growth. A major challenge with AE when applied to aircraft, and other complex structures, is that wave propagation is significantly affected by stiffeners, holes, thickness changes and other complexity. This reduces the accuracy of traditional source location techniques, that are based on a singular propagating wave speed. The Delta-T method enables higher levels of accuracy by mapping the structure and accounting for these changes. In this work AE monitoring equipment was installed on a section of an aluminium Airbus A320 wing. Location trials showed the Delta-T technique improved the average error from 85mm to 23mm, for artificial Hsu-Nielson sources, compared to the commercial standard technique. Testing under fatigue however demonstrated the challenges encountered when inspecting 3D structures (due to multiple signal paths) with significant levels of background noise. Of two cracks identified in the structure, the first of these was successfully detected and located, whilst the other was missed due to high machine noise and unrepresentative loading.
Preliminary studies of flight sensoring for loads and aeroelastic parameters estimation of the NGCTR-TD wing
Authors: Cardozo A , Beretta J , Paletta N , Adden S , Belardo M , Chiariello A , Di Palma L
Published: January 2021

The paper presents the preliminary analyses carried out to estimate the accelerom-eters and strain gauges optimal configuration for the in-flight natural modes and internal loads identification of the Next Generation Civil Tilt Rotor Technology Demonstrator (NGTCTR-TD) wing.

The optimal accelerometers’ configuration has been achieved with the aeroelastic model by taking into account the modal displacements of the targeted natural modes, requirements of space availability and accessibility. A further analysis has been set up to estimate the accel-eration peak on the wing by using a continuous turbulence model with a von Karman power spectral density.

The optimal strain gauges’ configuration has been achieved as a subset of an initial layout by using the Skopinski methodology, where quality ratios and percentual errors lead to the identification of redundant and irrelevant measurements. This approach aims to recover the flight loads on the wing from an optimal set of strain measurements during flight. The present work has been a numerical study. A verification of the final Load Evaluation Matrix (LEM) has been performed using a set of validation load cases.
Methods of analyzing isolated and ducted fixed-pitch propellers under non-axial inflow conditions
Authors: Cerny M , Faust J , Breitsamter C
Published: January 2021

Currently, a growing interest for the propulsion of unmanned aerial vehicles (UAVs) can be recognized. To adress this, small-scale fixed-pitched propellers are analyzed in this work, both in isolated and ducted configurations. Due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reversed inflow, having a major influence on the flow field around a propeller. In order to investigate this influence, all analyses are performed at a range of inflow angles from αdisc = 0° to 180° relative to the propeller axis. This paper employs different numerical techniques and compares them regarding their capability of showing the influence of non-axial inflow on propeller configurations. Wind tunnel experiments are performed measuring the forces and visualizing the flow field with PIV as well as steady and unsteady RANS simulations are applied to study details of the flow field.
Study on a twin-fuselage transport airplane model in a low speed wind tunnel
Authors: Chernousov V I , Krutov A A , Pigusov E A
Published: January 2021

This paper presents the results of experimental studies of the twin-fuselage transport airplane model at the cruising configuration in the T-102 TsAGI low-speed wind tunnel. The researched twin-fuselage transport airplane is a tri-engine transport aircraft intended for transportation of cargo weighted up to 40 tons at a distance up to 3000 km with speed 700-740 km/h. The aerodynamic configuration has the two fuselages distributed under high-wing, and a “TT” – shaped tail. The research purpose was the determination of the aerodynamic characteristics of the twin-fuselage transport airplane model without engine nacelles and assessment of the twin-fuselage layout impact on control surfaces efficiency. The effect of installing an external cryogenic fuel tank under the wing between the fuselages of the model was considered too.
Sustainability: key to enable next generation supersonic passenger flight
Authors: Hardeman A B , Maurice L Q
Published: January 2021

The 2020 global Covid-19 pandemic has shocked the aviation system to its core, showcasing what the loss of this economic engine can do to the world’s economies and societies. This crisis also presents an opportunity to create new capabilities and outlooks. Commercial supersonic flight is one such capability. The availability of advanced computational designs and propulsion systems, new materials, route optimization and alternative fuels means that supersonic aviation can be part of that future in a sustainable manner.

Boom’s ultimate goal is to mainstream supersonic air travel and make it accessible to millions of passengers per year. Long-term projections of business-class airline demand suggest a total market of 1,000 to 2,000 commercial supersonic aircraft operating on more than 500 primarily transoceanic routes that will benefit from speeds twice as fast as today’s aircraft.

Given the increased focus on mitigating aviation’s environmental impact, bringing a new aircraft to market in the 2020s requires a careful focus on sustainability. To ensure public acceptance supersonic aircraft manufacturers and operators will have to proactively engage with stakeholders to address their concerns and focus on integrating sustainability solutions across their business strategies.

Boom is the first commercial aviation OEM to build sustainability into its aircraft programmes from day one, ensuring that sustainability considerations form an integral part of every aspect of the production process. A sustainability commitment to cover every step in the aircraft development cycle, from design and test through in-service operations and end-of-life recycling is key to successfully reintroduce commercial supersonic flight in the years ahead.
Conceptual design of a novel Unmanned Ground Effect Vehicle
Authors: Papadopoulos C , Mitridis D , Yakinthos K
Published: January 2021

In this work, a methodology for the conceptual design of a combined Box-wing and Blended-Wing-Body unmanned aerial platform, which exploits the ground effect, is presented. Ground Effect Vehicles (GEVs) are aircrafts or aerial vehicles capable of flying very close to the surface of water areas, being a promising alternative to ships and seaplanes operating in closed seas. In order to exploit the air cushion that is formed underneath, GEVs have low Aspect Ratio wings. Thus, the Blended-Wing-Body (BWB) layout configuration is an appealing choice due to the large available body surface. On the other hand, a tailless vehicle having the BWB layout is facing challenging stability issues, especially in a turbulent and highly volatile environment as the one close to the sea level. Therefore, the addition of the Box wing configuration, namely a continuous-surface nonplanar wing formation with no wing tips, is deemed beneficiary as a way to overcome the stability challenges and eliminate the wingtip vortices. The combination of these two prominent platforms leads to improved aerodynamic performance and eventually, a reduced fuel consumption. The design methodology starts by the estimation of the most important design parameters, such as aspect ratio, sweep angle, and taper ratio, which are continuously refined in an iterative computational framework during the conceptual design phase. In an initial approach, the flight scenario with no ground effect interference is studied, with the use of both analytical calculations and computational fluid dynamics simulations. The results from the conceptual design phase indicate that the UGEV configuration has a considerable potential as an alternative to ships or seaplanes, based on its ability to carry larger payload than seaplanes and deliver it faster than ships.
Geometry Model and Approach for Future Blisk LCA
Authors: Fricke Kilian , Gierlings Sascha , Ganser Philipp , Venek Tommy , Bergs Thomas
Published: January 2021

Air traffic is expected to double over the next 20 years and Flightpath 2050 targets to a 70 % reduction of CO2 and a 90 % reduction of NOx. Optimization of future aircraft engines often is dominantly driven by a focus on the reduction of fuel burn and emissions during operation. To identify additional environmental improvement potential a full Life Cycle Analysis (LCA) shall be aspired also including Materials, Processes and Resources, Manufacture and Production, Lifetime Services as well as Reuse, End-of-Life and Recycling. Core engine components, for example integral rotors, are comprised of Titanium-or Nickel-alloys and require complex manufacturing processes.

A geometry design model of a compressor blisk is introduced which is employed as basis for a future LCA approach focusing on materials, processes and resources as well as manufacture and production. The model is a carrier for challenging manufacturing features such as large blade twist, high aspect ratio and small blade gaps. In addition to the geometry model, a first set of multiple technology scenarios and their process chains will be introduced which will serve as base for a future LCA.
Selecting figures of merit for a hybrid-electric 50-seat regional aircraft
Authors: Moebs N , Eisenhut D , Bergmann D , Strohmayer A
Published: January 2021

In the course of the aircraft design process for a hybrid-electric aircraft, a number of configuration alternatives have to be assessed. In addition, novel propulsion concepts have to be compared to a conventional reference aircraft. These comparisons are carried out by means of suitable figures of merit, adapted to a reference mission. This work will give insight into the process of identifying suitable figures of merit for a 50-seat hybrid-electric regional aircraft, which was carried out in the Horizon 2020 project FutPrInt50. Coming from a thorough perspective, a down-selection leads to a graspable number of parameters which are categorized in regard to the environment, to the airline desirability, and to the introduction of hybrid-electric aircraft. Those figures of merit, like emissions and operating costs, are gathered in an objective function which can support an overall evaluation of the aircraft design. This offers a detailed, yet transparent assessment of the various designs.
Optimal Energy Management of a Hybrid Electric Helicopter for Urban Air-Mobility
Authors: Donateo Teresa , Pascalis Claudia Lucia de , Strafella Luciano , Ficarella Antonio
Published: January 2021

In this study, a hybrid electric helicopter for air-taxi operations is considered. The drivetrain includes a turboshaft engine and two electric machines, fed by a lithium ion battery. In previous works, some of the authors developed a simple but thorough modelling approach for the electric path of the power system that was validated by means of experimental data from literature. In this investigation simulation results from the Gas-turbine Simulation Program (GSP) commercial environment were used to develop and validate an off design model for the turboshaft. The second innovative contribution of the paper is the application of Dynamic Programming to four different missions of the helicopter to quantify the fuel saving potentiality of hybridization and also as benchmark for future online control strategies. A constraint was considered in the investigation to allow at any time the electric backup in case of engine failure. The results of DPM showed that it is possible to obtain a reduction of fuel burn from 12% to 24% (with respect to using only the engine to move the rotor) depending on the specification of the mission and the state of health of the battery. Moreover, it was proved that charging the battery on board is not necessary in this kind of application.
Wing conceptual design for the airplane with distributed electric propulsion
Authors: Hospodár Pavel , Klesa Jan , Zizkovsky Nikola
Published: January 2021

This paper is focused on the usage of distributed electric propulsion (DEP) in order to increase aerodynamic efficiency. A ten seats aircraft is used as a case study. New design uses the existing fuselage, tail and turboprop engine, only wing is completely redesigned. The cost function for the design procedure consists of two parts. The first one is aerodynamic efficiency, which has a primary impact on fuel consumption, and the second one is weight of the wing. Lifting line theory with blade element momentum theory is used to design a wing geometry with DEP. Optimal geometry is also verified by CFD simulation. The estimation of the wing weight is needed for the second part of the cost function. This was done by the design of elementary wing parts under CS-23 regulation. The wing is assumed as full-aluminium with two spars. The main goal of this optimization is to redesign the wing for a given range and save as much fuel as possible.
Identification of resonant vibrations of the miniature unmanned airplane with contact and non-contact measuring techniques
Authors: Olejnik Aleksander , Rogólski Robert , Szczesniak Michal
Published: January 2021

The paper describes application of two different vibration measurement methods for identification of natural modes of the miniature UAV. The aim of this research was to determine resonant frequencies and modes of mini-airplane within specified range of frequency values. Special measuring equipment was used including both contact and non-contact techniques. The measuring systems on equipment of the Institute of Aviation Technology in the Faculty of Mechatronics, Armament and Aerospace of Military University of Technology (Warsaw, PL) were used to conduct measurements. In traditional GVT methods a large number of sensors can be attached to the aircraft. The weight of sensors and cables is negligible in relation to the mass of the large aircraft. But for small and lightweight unmanned aerial vehicles, this could bring a significant mass component in relation to the total mass of the tested object. In this paper the methodology of GVT was presented. Two different measuring methods were applied, i.e. the contact method and the non-contact method. Using the dedicated apparatus in relation to mini-airplane, properly prepared in terms of mass distribution, rudders deflection stiffness and proper support, some resonant characteristics can be determined. The contact measuring system consists of a multi-channel analyzer, piezoelectric accelerometers, electrodynamic exciters, amplifiers, impedance heads and a computer with the Test. Lab Software. As the non-contact method a laser scanning vibrometer was used. The principle of its operation is based on the separation of the emitted laser beam. The returning beam reflected from a vibrating object is captured by the camera and compared to the reference beam. Dedicated software analyses collected data and on the basis of it creates animations of structural vibrational shapes and spectral plots within investigated frequency range. Object used for research is the mini-UAV Rybitwa – composite mini-plane with a classic aerodynamic layout manufactured in IAT MUT. In the work both measurement methods and some sample results were presented. Results referenced to dynamic properties of the mini-UAV can be applied in the future to FE model tuning.
Direct method of rigidity using Mathcad Software
Authors: Koça Odhise , Sulejmani Anis , Alimhilli Parid
Published: January 2021

Static indeterminate structures are difficult structures to solve by hand or using classical methods. They required data and time to solve. New methods for calculating them are Direct Method of Rigidity (DMR). These structures, increasingly complex, are finding use in various fields of engineering as well as in the field of aviation and space. Therefore, introducing these methods into aircraft structures, helicopters or space structures is a pretty nice and difficult challenge. An example of this is the structure of a helicopter [1] and through DMR methods; we determine the internal forces important for other designations. The calculation procedure goes through several stages. The structure and its elements in local and global coordinates are studied, and then we create the matrix of rigidity. Through matrix transformations, it became possible to program algorithms for solving both methods in Mathcad software. In conclusion, we have all the graphs of the moment, the shear force and the normal force required for further studies of the structure.
Mini-Multi Interface Box Simulator (MMIBS)
Authors: Barea A , Doblado J G , Crespo D , Garcia A , Soldado I , Barrera G , Leopoldo A , Prats M M , Cabanas R M
Published: January 2021

Today’s military and commercial aircraft avionics and general systems are built around complex networks of intelligent devices. Maintenance and troubleshooting of these systems often require access to the data bus or networks connecting the system components. Whether it is on the integration test bench, Final Assembly Line (FAL) or at the Maintenance and Repair Organization (MRO), these tasks are usually performed by means of many, expensive, heavy and intrusive equipment. The MMIBS (Mini-Multi Interface Box Simulator) is a very compact, portable, multipurpose, lightweight, low-power, and easy-of-use electronics test means intended to improve digital aircraft ground testing and maintenance troubleshooting. It is capable of perform functional testing and simulating aeronautical equipment through most common aeronautical communication interfaces, such as AFDX, CAN BUS, ARINC 429, MIL-STD-1553, RS-422, RS-232, RS-485, Discrete and Analog I/O and RVDT (Rotary Variable Differential Transformer) reading capabilities. Besides, the system is highly configurable and reprogrammable by means of intuitive Python-based scripting. System is also able to be controlled with an intuitive, user-friendly and dedicated HMI (Human Machine Interface). In this mode, the user can conform a MMIBS WIFI network, allowing multiple MMIBS operating in parallel to cover complex testing scenarios. The MMIBS device integrates all the aeronautical communication and signaling in a volume of 12x12x12cm and weight of 1200g and provides an autonomy of 5 hours. In this way, our solution combines performance, reliability, low maintenance costs, and ease-of-use to support efficient ground maintenance operations.
Drag Control by Hydrogen Injection in Shocked Stagnation Zone of Blunt Nose
Authors: Vashishtha Ashish , Callaghan Dean , Nolan Cathal
Published: January 2021

The main motivation of the current study is to propose a high-pressure hydrogen injection as an hybrid active flow control technique in order to manipulate the flow-field in front of a blunt nose during hypersonic flight. Hydrogen injection can lead to self-ignition under the right environment conditions in a stagnation zone, and may cause thermal heat addition through combustion and provide the counterjet effect together by pushing bow shock upstream. The axisymmetric numerical simulations for the hemispherical blunt nose are performed at a Mach 6 freestream flow with 10000 Pa pressure and 293 K temperature. The sonic and supersonic hydrogen and air injections are compared for drag reduction at the same stagnation pressure ratio PR and momentum ratio (RMA). The sonic air and hydrogen injection scenarios show similar performance in terms of drag reduction and similar SPM flow features, but hydrogen injection has a mass flow rate 3.76 times lower than air. Supersonic hydrogen injection at Mj 2.94 behaves differently than supersonic air injection and can achieve up to 60 % drag reduction at lower PR and LPM mode with lower mass flow rate. Additionally, air injection achieves a drag reduction of 40 % in SPM mode at higher PR with very high mass flow rate.
Artificial neural networks in panel method for solving aerodynamics problem
Authors: Strelets D Yu , Kataev A A , Khrustalev A L
Published: January 2021

The authors proposed an experimental panel method combined with an artificial neural network to solve the problems of aerodynamics with minimum computational power consumption and high accuracy. A software solution based on the proposed method has been created. A comparison with experiments and other existing solutions has been made. The proposed method is intended for solving aerodynamic problems in systems of multi-criteria optimization, as well as in related problems. For example, solutions to the problem of strength and aerodynamics in the associated wing of a civil aircraft. The proposed method and software solution based on it can open new horizons in aerospace industry optimization calculations.
Textured solar cell modeling in TCAD
Authors: Plotnikova E YU , Arsentiev A V , Harchenko M E
Published: January 2021

We investigate one of the promising methods for increasing the output characteristics of solar cells - surface texturing. The structures and characteristics of microcrystalline silicon solar cells are simulated. Solar Cells with different surface geometries are compared. The first type is the classic flat structure. The last and the most effective is Solar Cell with the surface in the form of microscopic pyramids separated by flat regions.
Analysis of assessment of the technical condition of equipment of generating systems
Authors: Sultanov M M , Baydakova N V , Afonin A V
Published: January 2021

This work presents the results of the analysis of existing methods for assessing the technical condition of generating systems’ equipment, the advantages of maintenance and repair systems by the actual condition are considered.
Improving the characteristics of thermoelectric generator batteries based on bismuth telluride by optimizing the parameters of hot pressing n-Bi2Te2.4Se0.6
Authors: Grebennikov A A , Bocharov A I , Makagonov V A , Kalyadin O V , Yur’yev V A , Korolev K G
Published: January 2021

The effect of hot pressing modes (pressing pressure and holding time under pressure) on the thermoelectric properties of n-type bismuth telluride Bi2Te2,4Se0,6 doped with Hg2Cl2 was investigated. Samples were obtained by powder metallurgy technology - the synthesis of a chemical compound followed by hot pressing. A change in the hot pressing modes does not significantly influence the value of the thermo-EMF and conductivity of the samples. A change in the hot pressing mode significantly influences on the value of thermal conductivity. Both the increase of pressing pressure and the increase of the holding time under pressure leads to a decrease in the thermal conductivity of the material. Thus, the thermoelectric figure of merit of bismuth telluride can be increased by increasing the pressing pressure, holding time under pressure, or both parameters simultaneously. The increase of the thermoelectric figure of merit was 15% in the investigated samples. As a result of the tests of thermoelectric generator batteries, it was found that the output power of the battery made from a material with a high figure of merit was 27 W at temperatures 70 °C on the cold side, 300 °C on the hot side. The output power of the battery which was made from the material with a lower figure of merit was 25 W at a similar temperature regime.
Heat consumption of apartment buildings during the heating period
Authors: Kitaev D N , Cheremisin A V , Hasanov Z S , Mikhailov A A
Published: January 2021

The work is devoted to the search for methods for calculating the heat consumption of multi-apartment residential buildings for heating and hot water supply, which allows obtaining the closest results to the actual ones. Three current methods of calculating heat consumption and one canceled, but often used in heat supply contracts, were used. Based on a comparison of the actual data obtained by the common-house heat energy metering devices and the calculated values, the possible deviations in the heat consumption of multi-apartment residential buildings of different floors, area and year of construction, ranging from 49.73 to 177.77%, were found. An economic assessment of the consequences of using the most inadequate methods has been carried out. It was found that when using methods with extreme error values, payments for the heat supply service from one house can differ by 3.6 times.
Analysis of technical condition and development of practical recommendations to improve the reliability of steam turbine control system
Authors: Sultanov M M , Lunenko V S , Chubko Y M
Published: January 2021

Questions of ensuring reliability and safety of operation of complex technical systems are relevant during the operation of power equipment of thermal plant (TPP). The paper presents a generalized statistical analysis of defects and damages over the past 15 years in the control systems of steam turbines of types ET (extraction turbine) and IET (industrial extraction turbine), with an installed capacity of 50 to 135 MW. As a result of the calculation study, the main cause-and-effect relationships of the resulting defects that lead to an emergency stop of the turbines were identified. This paper presents the results of the analysis of defects in steam turbine control systems and provides recommendations for eliminating and preventing unplanned downtime due to an emergency shutdown of turbine units.
Application of digital twins of equipment for managing complex renewable energy
Authors: Smirnov A A , Lunenko V S , Boldyrev I A
Published: January 2021

The paper describes a control system for renewable energy complexes with optimization of operating modes based on digital twins of equipment. The application of digital twins allowed us to develop a simulator that simulates the main processes occurring in the ground heat pump system. The simulator allows: to perform computer experiments to study different modes of Polygon operation; to demonstrate the physical essence of the ongoing processes to form the qualifications and skills of students in the field of non-traditional and renewable sources of electric and thermal energy. The use of digital twins also allows the implementation of a renewable energy combination management system to improve the energy efficiency of hybrid power complexes. The algorithm developed by the authors for selecting combinations of renewable energy sources to increase the energy efficiency of the complexes takes into account the current values of the operating parameters of the equipment, the forecast of energy consumption, as well as the forecast of power generation by each of the components of the complex.
Reliability assessment of gas supply to individual consumers using digital modeling
Authors: Martynenko G N , Petrikeeva N A , Gorskikh S A , Gorskikh A A
Published: January 2021

In this work, an algorithm for assessing the reliability of gas supply for individual enterprises was developed and a block diagram of the application program was compiled. The calculation was made in accordance with the principles of the theory of the probability of disconnecting consumers using digital modeling.
Hardware solutions for connecting static capacitor banks in high voltage electrical networks
Authors: Babenko V V , Khaichenko I A , Nefedov Yu V , Krysanov V N
Published: January 2021

This work is dedicated to finding effective hardware solutions for implementing the power part of reactive power compensation units for high voltage electric networks. It shows the possibility of cooperative usage of thyristor and electromechanical key elements for switching static capacitor batteries in high-voltage networks. Based on the suggested hardware solutions main technical and cost characteristics of thyristor capacitor units are determined. The rationality of their use in industrial high-voltage electrical networks of 6-10 kV is concluded. It is shown that the usage of hybrid thyristor capacitor units allows one to reduce the expenses, to provide the required range of accuracy of reactive power regulation, to cut power losses in the network, to guarantee normalized voltage level in the load nodes and to increase the reliability and duration of power equipment life cycle.
Numerical study of the effects of pressure gradient on the heat transfer in the KMS heat exchanger channel
Authors: Petrova N , Tsynaeva A
Published: January 2021

The work is devoted to studying the influence of the pressure gradient on the heat transfer intensity in the channel of the KMS air heater. The aim of the work is to develop methods for improving the heat engineering characteristics of a heat exchanger using a pressure gradient. Numerical simulation is implemented based on the RANS approach using the Code Saturne software package using the k-w-sst turbulence model. The simulation conditions were set in accordance with the manufacturer’s instructions for the KMS-2 type air heat exchanger. In the work, the heat transfer coefficient was studied in the presence of a longitudinal pressure gradient in the heat exchanger channel from the gas path. As a result of the simulation, data were obtained on the effect of the pressure gradient on the heat transfer intensity for different working fluids in the channel of an advanced heat exchanger.
Flow simulation of petroleum diesel fuel and rapeseed oil in the nozzle of a diesel injector
Authors: Sa Bowen , Markov Vladimir A , Kamaltdinov Vyacheslav G , Neverov Vsevolod A
Published: January 2021

The flow of petroleum diesel fuel (DF) and rapeseed oil (RO) in the nozzle of a diesel injector under operating conditions was simulated numerically. Investigated the general flow characteristics, such as mass flow rate, discharge coefficient, injection rate, averaged turbulent kinetic energy at the nozzle outlet and volume concentration of fuel vapor in the nozzle, and local flow parameters. The saturation pressure of RO is determined by summing the saturation pressure of constituting RO triacylglycerides. At a fuel temperature of 40 °C, the mass flow rate, discharge coefficient, injection velocity and turbulent intensity at the outlet of the nozzle hole for RO are significantly less than petroleum DF for all injection pressures, and the RO cavitation level (fuel vapor) in the nozzle hole is also lower than petroleum DF due to extremely slow saturation pressure of RO. However, this difference between RO and petroleum DF decreases with increasing injection pressure due to the different cavitation levels of DF at different injection pressures.
Investigation of the influence of gravitational forces on the thermal-hydraulic processes of power plants
Authors: Sataev A A , Andreev V V , Duntsev A V , Novikov D I , Berezin A A
Published: January 2021

Today, improving the safety of nuclear power plants is one of the main problems. Obviously, heat and mass transfer processes have a great influence on complex phenomena occurring in the reactor plant. Currently, special software systems are being developed that can describe these processes (Computational Fluid Dynamics (CFD)). However, they do not take into account the influence of external gravitational forces. They occur when the spatial position of an object changes. In the case of ship-based nuclear power plants, the development of technical specifications should include a mandatory requirement for trouble-free operation when affected by pitching and rolling. The paper describes the study of the effect of shipboard pitching on the mixing processes of non-isothermal flows in a small-scale model. Based on the analysis of the results obtained, it can be concluded that the external dynamic force has a negative effect on the mixing of non-isothermal flows.