bluuebunny/crossref_metadata_2025 huggingface dataset:
Grain boundary plasticity initiated by excess volume
Authors: Zhu Qi , Zhao Qingkun , Huang Qishan , Chen Yingbin , Suresh Subra , Yang Wei , Zhang Ze , Zhou Haofei , Gao Huajian , Wang Jiangwei
Published: March 2024

Grain boundaries (GBs) serve not only as strong barriers to dislocation motion, but also as important carriers to accommodate plastic deformation in crystalline solids. During deformation, the inherent excess volume associated with loose atomic packing in GBs brings about a microscopic degree of freedom that can initiate GB plasticity, which is beyond the classic geometric description of GBs. However, identification of this atomistic process has long remained elusive due to its transient nature. Here, we use Au polycrystals to unveil a general and inherent route to initiating GB plasticity via a transient topological transition process triggered by the excess volume. This route underscores the general impact of a microscopic degree of freedom which is governed by a stress-triaxiality-based criterion. Our findings provide a missing perspective for developing a more comprehensive understanding of the role of GBs in plastic deformation.
Adaptive HD-sEMG decomposition: towards robust real-time decoding of neural drive
Authors: Yeung Dennis , Negro Francesco , Vujaklija Ivan
Published: March 2024

Objective. Neural interfacing via decomposition of high-density surface electromyography (HD-sEMG) should be robust to signal non-stationarities incurred by changes in joint pose and contraction intensity. Approach. We present an adaptive real-time motor unit decoding algorithm and test it on HD-sEMG collected from the extensor carpi radialis brevis during isometric contractions over a range of wrist angles and contraction intensities. The performance of the algorithm was verified using high-confidence benchmark decompositions derived from concurrently recorded intramuscular electromyography. Main results. In trials where contraction conditions between the initialization and testing data differed, the adaptive decoding algorithm maintained significantly higher decoding accuracies when compared to static decoding methods. Significance. Using “gold standard” verification techniques, we demonstrate the limitations of filter re-use decoding methods and show the necessity of parameter adaptation to achieve robust neural decoding.
Analysis of Springback Characteristics of Bending Unloading for Stainless Steel tubes
Authors: Xiong Zhi , Zhao Gangyao , Zhang Ranyang , Guo Zhenghua , Tian Yuan , Yang Zhenyu
Published: March 2024

Stainless steel tubes are widely used in piping systems in aviation, aerospace and other high-tech fields because of their high strength, excellent corrosion and high-pressure resistance, and good resistance to high-temperature oxidation. This paper takes 304 stainless steel pipe as the research object, based on ABAQUS finite element platform, the springback behaviour of stainless steel pipe in the process of precise bending and forming has been studied in depth. The results show that: pipe bending unloading bending springback angle increases with the increase of the bending angle. The results of the study have important theoretical and practical significance for improving the accurate forming and springback of stainless steel tube bending.
Study on the Method of Coating Defect Elimination and Effect on Mechanical Properties
Authors: Meng Chao , Ma Zhandong , Ding Yingying , Wang Jigang
Published: March 2024

The casting method in coating preparation has the advantages of short sample preparation period, small raw material loss, low cost, but the paint film often has bubble defects.The defects were characterized by microscope observation and density balance test. The influence of solvent content and ultrasonic shock on coating defects and the influence of defects on coating mechanical properties were investigated. The results show that the density decreases linearly with the increase of the number of bubbles. With the increase of solvent, the viscosity of paint decreases and the content of bubbles decreases obviously. As solvent increased, coating drying time increased, sample preparation period increased.After ultrasonic shock, bubbles in the surface of the paint and the cured coating were significantly reduced, compared with spraying sample preparation, ultrasonic shock sample preparation period was shortened by more than 30%.The samples with defective mechanical properties were broken during bubble emergence, the tensile strength and elongation at break were significantly reduced, and the dispersion was large, which was invalid data.
Solidification and Super-cooling Behaviors of Silica Nanofluids based on the Molten Eutectic Nitrate Salt
Authors: Sun Wei , Liu Xiangchen , Zhang Hui , Wu Yunyi , Li Baorang
Published: March 2024

SiO2 nano-powders with different particle sizes were used to fabricate nitrate-based nanofluids with the nano-particle concentration arranged from 0.5-4.0 wt.%. The crystallization process of the as-prepared composite and the influence of nanoparticles on the cooling kinetics was analyzed based on experimental data. The research results show that Johnson-Mehl-Avrami equation can be only used to describe the crystallization process of pure eutectic salt, but not suit for nanofluids since the nanoparticles addition can alter the crystallization kinetics of the composites. Depending on the particle size and concentration, nanoparticles addition was found to be able to improve the degree of supercooling and reduce the crystallization completion time by varying degrees. Further verification by a modified JMAK equation shows that with the nanoparticle addition, the component ‘n’ would fluctuate within a certain range, which indicates that the nanoparticles can improve the crystallization process by altering the nucleation mechanism and adjusting the cooling rate resulted from the increased thermal conductivities of the nano-fluids.
Effect of Post-heat Treatment on Microstructure and Mechanical Properties of Laser Cladded High Co-Ni Secondary Hardening Steel Coating
Authors: Qin Renyao , Chen Bingqing , Zhang Guohui , Liu Wei , Li Neng , Huang Shuai , Gao Chao
Published: March 2024

The effect of post-heat treatment on the microstructure and microhardness of laser cladded high Co-Ni secondary hardening steel coating was investigated. The microstructures were analyzed using a SEM equipped with an EDS, and the microhardness was measured with a Vickers indenter. Decomposition of the retained austenite in the coating occurred during the post-heat treatment. As the temperature increased from 200 °C to 600 °C, the quantity of the retained austenite at the boundaries decreased significantly, while that of the needle-shaped M3C cementite and M2C carbides increased. The M2C carbides evidently coarsened when the temperature was higher than 500 °C. The microhardness of high Co-Ni steel coating increased as the temperature of post-heat treatment increased from 200 °C to 400 °C because the fine-scale M2C carbides were coherent with the matrix and increased distinctly in this temperature range. It decreased sharply when the temperature further increased from 500 °C to 600 °C due to both the incoherency of the coarsened M2C carbides and the recovery of dislocations in the carbon-supersaturated matrix.
Preparation and Properties of Graphene/Novel Degradable Plastics Hybrid Low Enthalpy of Phase Transition Materials
Authors: Wang Hongyang , Wang Shu , Feng Jie
Published: March 2024

Graphene (GNs) were chosen to modify hybrid and novel degradable plastics PTLA/polymethyl methacrylate (PMMA). The low enthalpy of melting phase transformation (MEPT) materials (PTLA/PMMA)/GNs were prepared by adding the GNs at different mass fraction(1%, 2%, 3%, 4%) into PTLA/PMMA, and the properties of the hybrid phase change materials were characterized. The results indicated that the MEPT of PTLA/PMMA materials can be significantly reduced with the addition of GNs. The addition of 3% (mass) GNs made the MEPT of PTLA/PMMA material decreased by more than 50%. With the increase of GNs mass fraction, the MEPT hardly changed; Fourier transformed infrared (FT-IR) spectra showed that the interaction between GNs and PTLA/PMMA was physical; Scanning electron microscope (SEM) images showed that the components of GNs and PTLA/PMMA were mixed evenly without phase separation; The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) cycle performance tests showed that the decomposition temperature of the (PTLA/PMMA)/GNs material was up to 280 °C, and the properties could remain stable during the circulation process. The addition of GNs could effectively reduce the MEPT of the (PTLA/PMMA)/GNs material, increase the heat transfer efficiency, and have good thermal reliability.
Review on Multi-pass Rolling Forming of Thin-walled Ring with Complex Section
Authors: Lu Keliang , Zhao Gangyao , Guo Zhenghua , Zhang Ranyang , Yu Dongliang
Published: March 2024

Superalloy thin-walled ring with complex cross section plays an important role in aerospace, energy and chemical industry, and it has excellent mechanical properties and oxidation resistance in high temperature and pressure environment. However, multi-pass rolling forming of thin-walled ring with complex cross-section of superalloy is a complex forming process that needs to undergo complex uneven plastic deformation under the coupling of multiple fields and factors. The research progress of multi-pass rolling forming of superalloy thin-walled ring with complex cross section is summarized from three aspects: deformation behavior and stress analysis, defect behavior analysis, process optimization and simulation, and several directions that need further research in the future are put forward.
A Method of Preparing a Microcapsule with High Thermal Conductivity and Its Application
Authors: Wu Yi , Huang Zhonghui , Zhang Yining , Li Dian , Mo Ziliu , Lu Li , Liu Jialei
Published: March 2024

Microcapsules are widely used to add aroma to cigarettes and electronic cigarettes. However, at present, many cigarettes containing aroma microcapsules release insufficient aroma and the active ingredients cannot be fully released, which is due to the fact that the wall materials for preparing such microcapsules are mainly organic molecules, resulting in low thermal conductivity of such microcapsules. Moreover, these materials suffer from uneven distribution, low loading rate, uncontrollable preparation, etc., and has a limited effect on the thermal conductivity of microcapsules. In this study, aromatic and highly thermally conductive microcapsules were obtained by reaction using β-cyclodextrin as wall material and expanded graphite and menthol as core material. It was found that the thermal conductivity of the microcapsules increased exponentially with the increase in the amount of expandable graphite added, and this also indicates a gradual increase in the loading of the core material in the microcapsules. Further, the microcapsules have a high decomposition weight loss temperature, and there is no effect of using them in cigarettes and electronic cigarettes. Moreover, the microcapsules contain menthol, which can enhance the aroma of cigarettes.
Experimental Study on the Mix Proportion Optimization of Full Tailings Concrete
Authors: Yu Zikang , Bai Lihua , Yang Mingjing , yuan Jing , Sun Jianheng
Published: March 2024

Full iron tailings concrete can effectively use iron tailings as the raw materials of concrete. This paper used iron tailings powder, iron tailings sand and iron tailing gravel to replace fly ash, river sand, and ordinary gravel as concrete admixtures, fine and coarse aggregates, respectively. The orthogonal experimental method was used to optimize the mix proportion of C40 strength grade full iron tailings concrete. Research results showed that the optimal mix proportions of C40 strength grade full iron tailings concrete was water cement ratio 0.34, sand ratio 39%, and water reducing agent 0.4%.
Research on Off-axis Aberration Optimization Model for Bifocal Glass Lens
Authors: Kao Chih-Chen , Hsueh Bo-Ren , Wu Bo-Wen
Published: March 2024

Presbyopia entails the gradual deterioration of the eye’s ability to focus, and bifocal lenses have become a common remedy to alleviate blurred near vision and counteract eye strain induced by prolonged usage. The refractive index and Abbe number of these lenses play a crucial role in precisely correcting focal points within the near vision range. Nevertheless, when light rays approach the lens at off-axis angles or with tilts, aberrations occur, often with uneven distribution across real glass materials. The amalgamation of bifocal lenses further compounds the complexity of these aberrations. To enhance the correction of aberrations in bifocal glass lenses, distortion and astigmatism aberration serve as input parameters to calculate the optical quality assessment of the lenses. This study introduces a novel approach to optimize the pairing of bifocal glass lenses through the Taguchi method and fuzzy inference. The experimental design involves the application of the LS9 orthogonal array, streamlining the number of experiments while upholding the reliability of experimental data. The objective is to refine the selection of glass lenses and successfully devise an optimized design model that can be effectively applied to the configuration of bifocal glass lenses.
Optical and Electrical properties of KNN-SBN:Ho/xYb Transmittance Luminescent Ferroelectric Ceramics
Authors: Liu Kaishuo , Liu Haonan , Wang Mingchang , Yu Chengjian , Wang Liwen , Wang Hua , Xu Jiwen , Yang Ling , Qiu Wei
Published: March 2024

Transparent luminescent ceramics 0.94(K0.5Na0.5)NbO3-0.06Sr(Bi0.5Nb0.5)O3: 0.1Ho2O3/xYb2O3 (KNN-SBN:Ho/xYb, x=0.5, 1.0, 1.5, 2.0) have been synthesized using a solid-state reaction method.All the ceramic materials exhibit a pseudo-cubic structure without heterogeneous phases at room temperature. In addition, the microstructure of KNN-SBN:Ho/xYb transparent luminescent ceramics is very dense, and at the same time, good optical transparency is obtained, with a transmittance of 70.19% when x is 0.5. KNN-SBN:Ho/xYb transparent luminescent ceramics exhibit upconversion luminescence properties, and the best upconversion luminescence intensity is obtained when x is 1.5. The KNN-SBN:Ho/xYb transparent luminescent ceramics are ferroelectrics with good ferroelectric properties under an applied electric field of 120 kV·cm−1, and the maximum polarization intensity is the highest when x is 0.5, which is 21.32 μC·cm−2.
Simulation Research on Local Settlement of Kiln Foundation Based on Winkler Theory
Authors: Niu Xiaoyu , Ju Junpeng , Zhou Ming , He Lizhe , Zhou Yuan , Wang Yi , AbdulMajid Khan
Published: March 2024

The masonry structure is one of the main types of modern industrial buildings in China because of its local materials and simple economy. However, these buildings often suffer damage and cracks due to uneven settlement of the foundation and disrepair, which affects the safe and normal use of the structure. It is urgent to maintain and strengthen the structure to restore the safety of the structure. This paper takes Baoji Shenxin Yarn Factory - Kiln Factory as the actual engineering background, and use the finite element software ABAQUS based on Winkler’s theory to establish a finite element calculation model that can more conveniently respond to the effects of different foundation settlements. Through the simulation analysis, the influence law of the local settlement of the kiln foundation on the overall structural force state was obtained, which can provide an important reference basis for the maintenance and reinforcement of the structure.
A Flexible Electrochromic Device based on PEDOT: PSS Working in Visible and Infrared Band
Authors: Pu Ning , Ghosh Pintu , Li Qiang
Published: March 2024

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), a novel conducting polymer, has gained significant attention in the realm of electrochromism. In this study, we present the fabrication of a simple double-layer device utilizing PEDOT:PSS, which successfully achieves precise control of emissivity in the infrared band. Through comprehensive experimentation, we observe an impressive regulation amplitude of 0.25 and a temperature difference of 10°C, relative to a background temperature of 100°C. Additionally, the device exhibits remarkable flexibility compared to other existing devices. These findings demonstrate the potential of PEDOT:PSS-based double-layer devices as versatile tools for infrared emissivity modulation, holding promise for diverse applications in fields such as thermal management and energy-efficient technologies.
Parameter Investigation of Flyash Jet Mill with Superheated Steam
Authors: Li Jun , Zhang Hongyang , Hong Yun , Liu Lin , Hu Bin , Guo Yi Cliff , Liu Zhen
Published: March 2024

To improve the utilization rate of flyash, refining flyash is an important approach, and steam power grinding with superheated steam is an important equipment to meet the fine particle size requirements of flyash grinding. A 2.4 m height jet mill with four Laval nozzles has been employed here, and FLUENT is adopted to numerically simulate the distribution of fluid velocity and pressure in the flow field within the model. Meanwhile, parameter investigation is also carried out to reveal the effect of nozzle spacing and nozzle inclination angle on fluid filed and average particle velocity distribution. It is found that both spacing and nozzle inclination angle can affect the average particle velocity simultaneously. From the present parameter investigation, it can be concluded that Model 2 (nozzle spacing is 455 mm) with an inclination angle of 4° is the best choice since it can provide largest particle velocity distribution along the vertical direction.
Research Progress of Bio-organic Dust Suppressants
Authors: Yang Lurong , Hong Lei , Huang Jiabang , Jin Jie , Wu Ke , Zhu Shoucheng
Published: March 2024

Both natural and human-generated dust can cause serious harm to the environment and human health. Since the dust suppressants can accelerate the dust settlement more effectively to prevent the dust from raising; at the same time, to comply with the concept of environmental protection, the use of natural bioorganic materials to prepare dust suppressants has become a research hotspot. This paper summarizes the working principle of dust suppressants and the evaluation indexes of the performance of the dust suppressants, reviews the methods and research results of using bio-organic materials such as polysaccharides, lignin, proteins, microorganisms, agricultural and forestry wastes to prepare dust suppressants in recent years, and puts forward the suggestions on the problems of the current bio-organic dust suppressants to provide a reference for their further development in the future.
Research and Application of the Fourth Generation Stratified Water Injection Technology in Daqing Oilfield
Authors: Song XingLiang , Tong Yin , Jin Zhendong , ZhenkunZhu  , Liu Yuting
Published: March 2024

Stratified water injection is the most important characteristic technology in Daqing oilfield development, providing technical support for efficient oilfield development. With the oilfield entering the ultra-high water cut stage, the remaining oil is highly dispersed, the oil-water relationship is complex, the qualified rate of water injection decreases rapidly, and the difficulty of stabilizing oil and controlling water is increasing. In order to solve the contradiction between the increasing workload of water injection well testing and the limited testing team, and mee t the needs of oilfield precision development, the cable-controlled layered water injection technology has been developed. In this technology, the pressure monitoring system, flow monitoring system and flow control system are placed in the preset cable intelligent water distributor. At the office end, the technicians send control instructions on the server software, and send them to the ground control box through the oilfield production wireless network. The cable carrier technology is used to transmit the instructions to the intelligent water distributor through the cable, so as to achieve real-time communication, obtain the downhole layering parameter information, and control the downhole layering injection volume. Ten intelligent injection technology demonstration areas have been built to verify the process adaptability under different development contradictions. The cable-controlled layered water injection technology improves the proportion of water absorption thickness, effectively controls the water cut rise rate and natural decline rate, and has obvious oil increase effect, promoting the digital transformation and intelligent development of the oilfield.
MODELING of Water Saturation in Shallow Sandstone Oilfield
Authors: Wang Shuqin , Liu Minghui , Bo Bing , Ma Hongfei , Zheng Tianyu , Gao Yujie
Published: March 2024

3D geological modeling technology has achieved visualization of underground reservoirs in oil and gas fields, and has been widely applied in oil and gas field development. 3D geological modeling includes structural modeling and attribute modeling, and strata and faults can be completed based on data from oil and gas field exploration and development. The porosity and permeability in the geological attribute model can be established based on logging interpretation conclusions and other relevant data, The establishment of a saturation model has always been a difficulty in 3D geological modelling. As the water saturation, is different from porosity and permeability of an oil field. Saturation is distributed under the control of factors such as gravity and capillary force, and cannot be established through spatial simulation interpolation. Instead, the influence of factors such as gravity and capillary force should be considered. This article takes the shallow sandstone M oilfield in Kazakhstan as an example, and establishes the J function of the oilfield by combining the capillary pressure experiment of the core well, in order to establish an oilfield saturation model.
Case study of optimizing Low Impact Development Strategy in School: Allocation by the Drainage Distance
Authors: Xiao Wanting , Song Jusheng , Ma Xiang , Chen Chunyang
Published: March 2024

Under the concept of urban stormwater management, integrated efficiency of runoff and pollutant control via low impact development facilities came into focus, whereas a few specific descriptions are provided to quantify the strategy of these facilities, including the selection patterns of the locations and sizes and the connection of LID facilities and the drainage system, which is of important for the evolvement of LID strategy. Based on the weighted multi-object goal, the optimizing LID strategy reduces of runoff, pollutant, peak flow, and flooding time under required precipitation conditions, respectively. This paper concluded LID strategy under local requirements and tougher conditions in the aspect of the size and drainage distance of each facility, a new quantified index of locations of specific types of facilities. Then interpret the adjustment pattern based on the feature of rainfalls by correlation analysis. Correlation results show that the drainage distance of green roofs and the storage tank correlated to stormwater management indicators while the retention facilities did not, and the correlation respectively weakened and stronger when storm intensity increased, helping designers to establish better LID planning for schools.
Sensitivity Analysis and Optimization of a Liquid Cooling Thermal Management System for Hybrid Fuel Cell Aircraft
Authors: Habrard Valentine , Hazyuk Ion , Pommier-Budinger Valérie , Jézégou Joël , Benard Emmanuel
Published: March 2024

The objective of this work is to perform a comprehensive system analysis of a liquid-cooling thermal management system for a hybrid-electric aircraft using fuel cells for general aviation by sizing and optimizing the system with respect to a given objective. A sensitivity analysis on the different design parameters and model assumptions is also performed and their impact on the aircraft and its performances will be assessed. Firstly, the case study is defined and an optimization is run with some initial assumptions leading to a feasibility study for the implementation of this system. The sensitivity analysis is then undergone for the chosen coolant type and fuel cell stack temperature selected after the first optimization. Incorporating the findings of this analysis, a second optimization is run on the thermal management system with improved inputs in order to demonstrate a scenario with reduced penalty on the aircraft. Preliminary results show that implementing this hybrid propulsion system along with its thermal management is feasible with a reduction in payload and range. In addition, it can be concluded that initial assumptions and design choices are shown to have a significant impact on the system’s sizing and should be considered in aircraft sizing design loops.
Preliminary design of a retrofitted ultralight aircraft with a hybrid electric fuel cell power system
Authors: Donateo Teresa , Ficarella Antonio , Lecce Leonardo
Published: March 2024

Emission-free aerial propulsion can be achieved with a proton-exchange membrane fuel cell (PEM-FC). In the present investigation, this potential is addressed by designing a hybrid electric power system with fuel cells for an ultralight aerial vehicle to be retrofitted from a conventional fossil-fuelled piston engine configuration. The proposed power system includes a fuel cell, a lithium battery, and a compressed hydrogen vessel. A procedure is proposed to find the size of these components that minimizes the total mass and satisfies the target of a size below 200L and uses performance data of commercially available components. A comparison of different energy management approaches, with and without on-board charge of the battery, is performed. The results underline that the optimal solution is to select the size of the fuel cell to meet the cruise electric request and point out that the maximum discharge current of the battery must be regarded as a key issue in sizing this component, because of the very high take-off power.
Powertrain Design For Small Scale Parallel Hybrid-Electric Test Bench
Authors: Wilson Jamal , Salgado Dinis , Matlock Jay , Mazur Anna , Łowczycki Krzysztof , Widera Patryk , Zawadzki Kamil , Lipka Karol , Gęca Karolina , Suleman Afzal
Published: March 2024

Parallel hybrid-electric propulsion systems for small scale unmanned aerial systems (UAS) when tested with an internal combustion engine are susceptible to damage due to increased torque compared to all-electric configurations. The University of Victoria Centre for Aerospace Research has conducted testing and identified several locations in the system for potential upgrades. One of the largest issues identified was the electromagnetic clutch’s inability to handle the torque of the Corvid-50 engine. Thus, a new clutch and powertrain system was specified which is better rated for combustion operation. Similar findings are reported based on testing performed at Ł-Institute of Aviation, where a hybrid-electric powertrain stand experienced torque spikes. The spike amplitude was several times higher than the nominal momentum of the ICE, given in the specification sheets. In result, at some working modes, a strong slippage of the clutch has been observed. It is also of highest importance to propose and test potential methods to minimize momentum influence to the powertrain. The goal is to increase robustness of such hybrid systems, and decrease the overall mass of the system.
Comparison of Permanent Magnet Synchronous Machines for Hybrid Light Aircraft with traditional and additive winding technologies
Authors: Di Domenico G , D’Andrea M , Villani M , Jung J , Ottolinger R
Published: March 2024

Electrical motors are key components in the electrical transition required for greenhouse gas reduction programs. Future aircraft will certainly employ electrical motors for primary and secondary surface control, for landing gear and for other actuations such as high-lift systems, and they will also need electrical motors for propulsion. The motors pose the hardest challenge due to the high-power density required. Hybrid-Electric propulsion represents one of the most important topics in the aerospace industry and offers an opportunity to pursue the electrification change especially in light aircraft segments. The focus of this paper is the comparison among permanent magnet synchronous motors for Hybrid Light Aircraft propulsion with traditional and additive winding technologies.
High Fidelity Crash Analysis of Ngctr-TD Composite Wing
Authors: Di Palma L. , Albo G. , Nardone M. , Pezzella C. , Musella V. , Belardo M.
Published: March 2024

The T-WING project is a research project aimed at designing, manufacturing, qualifying and testing the new wing of Leonardo Next Generation Civil Tilt-Rotor technical demonstrator (NGCTR-TD), as part of Clean Aviation Fast Rotorcraft activities.

The methodology proposed in this paper encompasses the development of high-fidelity modelling and simulation procedures in support to virtual certification methods for crashworthiness requirements of tiltrotors. Finite Element Analysis (FEA) of an aircraft drop test is a complex and detailed process that aims to simulate the structural behaviour during an impact or drop event. This type of analysis is critical for assessing the safety of an aircraft in emergency landing situations. Wing crashworthiness requirement is specific for tilt rotors: during a survivable crash event, the wing design must ensure a pre-defined rupture with the purpose of alleviating the inertial load acting on the fuselage to preserve the occupants from injuries and fire, guaranteeing the escape paths. Thus, the highly integrated T-WING wing box concept has been designed with the specific feature of frangible sections near the wing-fuselage intersection. The activation of fracture of the external semi-wings in correspondence of frangible section is triggered by the achievement of a well-defined crash vertical load factor.

The objective of the methodology is to simulate the crash effects on the whole wing, using explicit non-linear and time-dependent FE analysis, to verify the wing spanwise placement of the frangible sections, the failure mode, the loads acting at the fuselage links, and the acceleration transmitted to the structure. This work is focused on a standalone analysis of the wing plus a lumped scheme of the fuselage, and it is part of a wider activity which will comprise, in the crash simulation, the most relevant vehicle systems (e.g. fuselage model). Moreover, this numerical activity has been compared with experimental results obtained on a different but similar structure, in terms of global acceleration at wing centre of gravity. Good agreement in terms of acceleration has been found between numerical model and experimental relevant test.
Vibration Response Analysis of a Main Landing Gear System for High In-Flight Dynamic Loadings
Authors: Arena Maurizio , Tartaglia Carmine Carandente , Bruno Giovanni , Bocchetto Francesco , Quaranta Vincenzo , Chiariello Antonio , Belardo Marika , Castaldo Martina
Published: March 2024

The prediction of aircraft vibrations is necessary for identifying possible design optimization points of each on-board system. In this context, the authors investigated the dynamic response of a Main Landing Gear (MLG) conceived for a fast helicopter when exposed to flight vibrations arisen from the engine propellers. The research activity falls within the Racer program of Clean Sky 2 framework, which aims to develop a novel high-speed rotorcraft. Relying on Airbus Helicopters operative requirements, this paper deals with the numerical procedure description of the MLG dynamic response assessment (resonance frequencies, accelerations amplitude, generalized masses) with respect to the expected in-flight vibrations levels. In particular, an equivalent combined load (sine and random spectrum) based on the normal modes and the corresponding modal mass distribution is employed for investigating the relevant effects on structural endurance. The central themes focus on the possible numerical modelling strategies and vibration loads analysis, which led safely to the qualification. This method could allow for performing sensitivity dynamic analyses in case of further design stiffness or weight changes.
Vibration Test campaign performed on a Landing Gear System
Authors: Tartaglia Carmine Carandente , Arena Maurizio , Bruno Giovanni , Bocchetto Francesco , Quaranta Vincenzo , Chiariello Antonio , Castaldo Martina , Belardo Marika
Published: March 2024

The landing gear system is one of the most critical systems of the aircraft. The need to design a landing gear with high performance, longer life and with a significant reduction in terms of weight, production and maintenance costs represents a real challenge for a sustainable future that Europe is heralding.

This paper presents the results of the experimental campaign of vibration tests performed on the main and side landing gear system, in both extended and retracted configurations, to be installed on the AIRBUS Group/Helicopter RACER compound helicopter demonstrator and it is part of the Project ANGELA within the European Research Program Clean Sky 2 Fast-Rotorcraft.

Furthermore, in this paper will be described the tailoring of the standard. The hybrid nature of the RACER, not envisaged in any of the categories of the standard, required a tailoring phase to test the landing gear systems in a conservative condition. Thus, it will be shown how this phase led to defining a test sequence, a test setup and the vibration loads. The test campaign, conducted with RTCA DO 160-G tailoring, is part of a wider experimental activity aimed at the development, production and qualification of processes and materials that will allow the landing gear system to achieve the “Permit to Flight”.
Sol-gel Chemistry Approaches for the Manufacturing of Innovative Functional Composites for the Aerospace Sector
Authors: Bifulco A , Imparato C , Passaro J , Malucelli G , Gaan S , Aronne A
Published: March 2024

Sol-Gel is a “bottom-up” synthesis method that enables the production of films, nano/microparticles, fibers, gels, and bulk materials, both glassy and crystalline. Sol-Gel chemistry can be a vital tool for solving problems in several industrial applications where nanotechnology is necessary to overcome constraints. Here, various examples involving silicate-based materials are discussed. Silicatic materials with a variety of morphologies and applications, e.g., monodisperse SiO2 particles ranging in size from a few nanometers to a micron, can be synthesized through hydrolysis and polycondensation reactions of silicon alkoxide precursors. Using an environmentally friendly electrospinning process, silica nanoparticles can be incorporated into polyvinylpyrrolidone (PVP) fibers to create novel, fire-resistant sound absorbers. Additionally, by employing hybrid techniques based on Sol-Gel, the flame retardance of nanocomposites made of silica and epoxy resin as well as epoxy-based composites including hemp, even cured with cycloaliphatic hardeners, can be enhanced. The development of novel materials beneficial for aviation applications, such as hydrophobic (potentially self-anti-icing) coatings, is a further proof of the effectiveness of Sol-Gel chemistry.
Design, Manufacturing, and Testing of a Metallic Fuselage Panel Incorporating New Alloys and Environmentally Friendly Technologies
Authors: Karanika Alexandra , Carelas Evangelos , Aldanondo Egoitz , Idel Snir , Abramoivich Alexander , Geest Marc Van Der , Visser Peter
Published: March 2024

Within the ecoTECH project, a new fuselage section was designed based on an existing business jet panel, aiming to incorporate innovative technologies and environmentally friendly approaches. The Metallic Fuselage Panel Demonstrator developed in this project integrates the most promising technologies previously developed in the areas of manufacturing methods, including mechanical milling and friction stir welding, as well as surface treatments such as sol-gel and thin film sulphuric acid anodizing, along with a Chrome-free primer applied on a new Al-Cu-Li alloy structure. Two types of full-scale testing were performed to mature the newly developed technologies and assess the performance of the demonstrator. The first was a Static Full-Scale Test Demonstrator, designed and manufactured to undergo static full-scale testing. This testing evaluated the structural integrity and performance of the panel under various load conditions, representative of an operational aircraft, including compression, shear, pressure, tension, and combinations of these forces. The second type of testing conducted concerned endurance. Similar to the static test demonstrator, this demonstrator was subjected to fatigue to assess its durability and long-term performance by simulating representative flight loading spectrum of a business jet aircraft and providing valuable insights into the panel’s ability to withstand prolonged operational conditions. The successful completion of these phases in the ecoTECH project represents a significant milestone, demonstrating the effective integration of innovative manufacturing methods and environmentally friendly surface treatments for new aluminum alloys in the development of innovative environmentally friendly technologies. The project’s outcomes contribute to the advancement of sustainable and efficient technologies in the aerospace industry, providing a foundation for the future development of aircraft structures with improved performance, durability, and reduced environmental impact.
Automated generation of aircraft on-board system architectures and filtering through certification specification requirements
Authors: Cabaleiro Carlos , Fioriti Marco , Boggero Luca
Published: March 2024

On-board systems represent an important part of an aircraft having a noticeable impact on mass and fuel consumption, among others. New innovative systems might increase the performance of the new generation of aircraft. Aircraft on-board system architectures are defined by the different subsystems, components and connections among them. The big amount of possible combinations usually creates a huge architectural design space that requires automation in order to be properly explored. Certification aspects can be used as a filter in early design stages of on-board systems, this allows to discard some architectures if they are not compliant with the certification specifications. The discarded architectures do not need to be sized and calculated, saving computational time. The proposed methodology shows how to create this link between on-board system architectures generation and certification rules. Results show an application case regarding the modelling of a flight spoiler system. Several architectures are automatically generated from the design space and then automatically filtered by the certification specification rules. This achieves a preliminary certification of innovative on-board system architectures and allows certification aspects to also drive the design process.
Game-theoretic learning for the coordination of drone teams in autonomous cooperative inspection
Authors: Pascarella D , Castrillo V U , Iudice I , Pigliasco G , Vozella A
Published: March 2024

Without the need for an on-board pilot, drones are designed to accomplish dull, dangerous and dirty missions. However, if a mission exhibits a large operative area and/or several objectives, it may entail poor performance when executed by a single drone. Drone teams may overcome this issue by acting as mobile sensor networks for proximal sensing. In such networks, cooperative autonomy is a key enabling behaviour for achieving resilient and cost-efficient systems. This work implements cooperative autonomous behaviour in the form of a dynamic and decentralized mission planner for a multi-drone inspection mission. The proposed design exploits multi-agent task allocation, distributed route planning and game theory for the assignment of inspection tasks and for the processing of optimal routes in reasonable time frames and with limited communication. In detail, it applies the learning-in-games framework for the coordination within the inspection team, by studying some ad-hoc variants of best response and of log linear learning. Moreover, this work presents some numerical results of model-in-the-loop tests for a comparison between the learning-in-games approaches.
Enhancement of multirotor UAV conceptual design through Machine Learning algorithms
Authors: Pliakos C. , Terzis D. , Vlachos S. , Bliamis C , Yakinthos K
Published: March 2024

Designing an efficient and optimized multirotor UAV requires laborious trade-off analyses, involving numerous design variables and mission requirement parameters, especially during the early conceptual design phase. The large number of unknown parameters, as well as the associated design effort often leads to non-optimal designs, for the sake of time efficiency. This work presents the implementation of a machine learning (ML) framework to assist and expedite the conceptual design phase of multirotor UAVs. The framework utilizes information from a comprehensive database of commercial lightweight multirotor UAVs. The database contains an extensive collection of crucial sizing parameters, performance metrics, and features associated with foldability and indoor guidance (e.g., obstacle avoidance sensors). These attributes specifically pertain to multirotor UAVs weighing less than 2kg, which exhibit diverse design and performance characteristics. The proposed ML framework employs multiple regression models (e.g. k-nearest neighbors regression, multi-layer perceptron regression) to predict the sizing parameters during a multirotor UAV’s conceptual design phase. This enables designers to make quick informed decisions, while also significantly reducing computational time and effort. Finally, the ML framework’s predictive capability is validated by comparing the predicted values with real-world data from an “unseen” test dataset.
Detail and structural design of a fixed-wing BWB UAV
Authors: Psarros A. , Kapsalis S. , Dimopoulos T. , Mitridis D. , Terzis D. , Giannakis E. , Panagiotou P. , Savaidis G. , Yakinthos K.
Published: March 2024

The current study focuses on the development of a prototype BWB UAV for highway traffic monitoring by supporting a Cooperative Intelligent Transport System (C-ITS). This system allows the monitoring of traffic conditions at large roads and highways. Having determined the mission requirements and concluded the aerodynamic conceptual and preliminary design phases, high fidelity CFD simulations are performed, aiming to calculate the key aerodynamic and stability characteristics of the platform and to optimize its performance throughout the mission. More specifically, regarding the aerodynamic vehicle design, results concerning the calculation of stability derivatives, control surfaces sizing, trim analysis and flight envelope (V-n diagram) are presented, along with the respective methodologies. Considering the structural design of the aircraft, a combination of layout, FE simulations and parameterized design tools were employed, allowing the design and sizing of the skin and the internal structural parts. The parts are mainly made of composite and additively manufactured nylon materials. Coupled interaction loops are conducted among the aerodynamic and structural analyses to optimize the overall performance of the aerial vehicle, maximizing the aerodynamic efficiency, and reducing the structural weight. Finally, the study is concluded by the presentation of the manufactured prototype of the UAV, which satisfies all the structural, aerodynamic, stability and performance requirements for the established highway traffic monitoring mission.
A step-by-step guide to include key electroencephalography (EEG) parameters in the study of human performance applied to air traffic control
Authors: Suárez María Zamarreño , Martínez Juan Marín , Moreno Francisco Pérez , Jurado Raquel Delgado-Aguilera , Frutos Patricia María López de , Valdés Rosa María Arnaldo
Published: March 2024

The study of human performance of air traffic controllers (ATCOs) is an interesting line of research to improve operational safety. In recent years, there has been an increase in the number of techniques available to develop this research based on massive data analysis. This study presents the use of certain electroencephalography (EEG) parameters to study the human performance of ATCOs. Although software and applications are now available to calculate these parameters, there are often problems in understanding the detailed process used to calculate them. The parameters presented in this study are intended to overcome this limitation and are applicable in real air traffic control (ATC) situations. Six parameters are analysed: excitement, stress, relaxation, boredom, engagement, and attention. As an application case for the parameters, a total of 50 data samples obtained during the development of real-time simulations on a highly realistic ATC platform are analysed. From these data, the above-mentioned EEG parameters and their trends are calculated. In addition, the evolution of these parameters is studied in relation to two other variables that characterise the operational situation of the sector during the simulations: the taskload based on ATC events and the number of simultaneous aircraft in the sector per minute.
More Haptic Aircraft
Authors: Zikmund P , Horpatzká M , Procházková H , Macík M
Published: March 2024

This paper presents a comprehensive review of haptic feedback in light aircraft control. It provides an overview of the results and experiences gained from a previous research project focused on the design and testing of pilot haptic feedback hardware. The objective of this paper is to outline a roadmap for the future development of “More Haptic Aircraft,” incorporating principles of human-centred design into light aircraft cockpits equipped with the presented haptic feedback device. The roadmap provides general requirements for pilot-aircraft interaction and highlights three specific levels of functions. These functions aim to reduce the pilot’s workload and enhance situational awareness.
Analysis of patterns and trends in air traffic behaviour in different en-route atc sectors using a complexity indicator
Authors: Moreno Francisco Pérez , Comendador Víctor Fernando Gómez , Jurado Raquel Delgado-Aguilera , Suárez María Zamarreño , Valdés Rosa María Arnaldo
Published: March 2024

Air traffic is currently increasing. But the ATC service, which is responsible for providing control of aircraft crossing the airspace, is unable to increase its capacity to cope with this demand. This makes airspace an increasingly complex environment. Complexity is thus becoming an area of interest. This paper aims to develop a complexity indicator based on the behaviour of the main flows of a sector. By means of Exploratory Data Analysis, it is possible to obtain a study that allows the complexity of different sectors to be compared with each other, as well as to analyse in detail the complexity of a sector or its causes. This exploratory analysis carried out for the study of complexity is very extensive, and can allow the ATC service to have a general or specific view of the complexity of the sectors, or even of the behaviour of certain air traffic flows. This is of great help, and can be a tool for optimising human and technological resources within the ATC service.