Pub Date : 2024-01-05DOI: 10.3390/aerospace11010054
Shilei Cao, Man Yang, Jian Liu
Due to its advantages of easy deployment and high stiffness-to-mass ratio, the utilization of truss structures for constructing large satellites presents an appealing solution for modern space missions, including Earth observation and astronomy. However, the dimensions of the traditional finite element model for a satellite with a large space truss structure become exceedingly large as the structure’s size increases. The control system design process based on the finite element model is complex and time-consuming. This paper employs the continuum modeling method to represent the truss structure as a continuous entity. The bending vibrations of the truss structure are encapsulated by a simplified partial differential equation (PDE), as opposed to the more intricate traditional finite element model. Simultaneously, the satellite’s attitude motion is characterized by an ordinary differential equation (ODE). Building upon this coupled PDE-ODE model, a boundary control law that only requires sensors/actuators at the boundary is formulated to effectively mitigate structural vibrations and regulate the satellite’s attitude. The exponential stability of this closed-loop system is scrutinized using Lyapunov’s direct method. The simulation results affirm that the continuum modeling method is indeed well-suited for satellites endowed with substantial truss structures, and the proposed boundary law proves to be highly effective in both attitude tracking and vibration suppression.
{"title":"Continuum Modeling and Boundary Control of a Satellite with a Large Space Truss Structure","authors":"Shilei Cao, Man Yang, Jian Liu","doi":"10.3390/aerospace11010054","DOIUrl":"https://doi.org/10.3390/aerospace11010054","url":null,"abstract":"Due to its advantages of easy deployment and high stiffness-to-mass ratio, the utilization of truss structures for constructing large satellites presents an appealing solution for modern space missions, including Earth observation and astronomy. However, the dimensions of the traditional finite element model for a satellite with a large space truss structure become exceedingly large as the structure’s size increases. The control system design process based on the finite element model is complex and time-consuming. This paper employs the continuum modeling method to represent the truss structure as a continuous entity. The bending vibrations of the truss structure are encapsulated by a simplified partial differential equation (PDE), as opposed to the more intricate traditional finite element model. Simultaneously, the satellite’s attitude motion is characterized by an ordinary differential equation (ODE). Building upon this coupled PDE-ODE model, a boundary control law that only requires sensors/actuators at the boundary is formulated to effectively mitigate structural vibrations and regulate the satellite’s attitude. The exponential stability of this closed-loop system is scrutinized using Lyapunov’s direct method. The simulation results affirm that the continuum modeling method is indeed well-suited for satellites endowed with substantial truss structures, and the proposed boundary law proves to be highly effective in both attitude tracking and vibration suppression.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"13 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.3390/aerospace11010051
R. Canumalla, T.V. Jayaraman
Titanium alloys, with their low density, exceptional mechanical properties, and outstanding corrosion resistance, play a vital role in various aerospace applications. Our decision science-driven assessment focused on metastable β, near-β, α + β, and near-α Ti alloys for landing gear applications, integrating multiple-attribute decision-making (MADM) methods, principal component analysis (PCA), and hierarchical clustering (HC) is based on current literature. The ranks of the alloys evaluated by diverse MADM methods were consistent. The methodology identifies five top-ranked Ti alloys assists and verifies the guidelines for alloy design. The top-ranked alloy, Ti1300-BM-nano-α (alloy chemistry: Ti-5Al-4V-4Mo-3Zr-4Cr, solution treatment: 800 °C for 1 h followed by air cooling—solution treated below β transus, and aging: 500 °C for 4 h followed by air cooling), stands out with a percentage elongation (%EL) ~3.3 times greater than the benchmark or goal (density, d = ~4.6 g/cm3; yield strength YS = ~1250 MPa; %El = ~5), while maintaining similar density and yield strength. The analyses underline that metastable β Ti alloys comprising globular primary α + trans β matrix coupled with α precipitates in trans β are the base optimal microstructure to fine-tune using thermomechanical processing for aircraft landing gear applications.
{"title":"Decision Science-Driven Assessment of Ti Alloys for Aircraft Landing Gear Beams","authors":"R. Canumalla, T.V. Jayaraman","doi":"10.3390/aerospace11010051","DOIUrl":"https://doi.org/10.3390/aerospace11010051","url":null,"abstract":"Titanium alloys, with their low density, exceptional mechanical properties, and outstanding corrosion resistance, play a vital role in various aerospace applications. Our decision science-driven assessment focused on metastable β, near-β, α + β, and near-α Ti alloys for landing gear applications, integrating multiple-attribute decision-making (MADM) methods, principal component analysis (PCA), and hierarchical clustering (HC) is based on current literature. The ranks of the alloys evaluated by diverse MADM methods were consistent. The methodology identifies five top-ranked Ti alloys assists and verifies the guidelines for alloy design. The top-ranked alloy, Ti1300-BM-nano-α (alloy chemistry: Ti-5Al-4V-4Mo-3Zr-4Cr, solution treatment: 800 °C for 1 h followed by air cooling—solution treated below β transus, and aging: 500 °C for 4 h followed by air cooling), stands out with a percentage elongation (%EL) ~3.3 times greater than the benchmark or goal (density, d = ~4.6 g/cm3; yield strength YS = ~1250 MPa; %El = ~5), while maintaining similar density and yield strength. The analyses underline that metastable β Ti alloys comprising globular primary α + trans β matrix coupled with α precipitates in trans β are the base optimal microstructure to fine-tune using thermomechanical processing for aircraft landing gear applications.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"57 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.3390/aerospace11010052
P. Sitompul, P. Razi, T. Manik, M. Batubara, M. Lathif, Farahhati Mumtahana, R. Suryana, Ibnu Nurul Huda, Taufiq Hidayat, Yana Taryana, F. Sobirin
After years of preparation, the Indonesia National Observatory, located in Mount Timau, Kupang Regency, is currently in the completion stage of research in astronomy and astrophysics and related subjects. An optic telescope with a 3.8 m diameter is expected to receive its first light in mid-2024. A feasibility study for Indonesia’s radio telescopes and networks is in progress. A single-dish parabolic radio antenna with a diameter of 20 m is proposed to work in a frequency range of 1–50 GHz. An array dipole antenna with an area of 100 m × 100 m will also be installed at a 70–350 MHz frequency. A feasibility study about system design is in progress, and a radio frequency interference (RFI) survey has been underway since 2014. In this paper, we described the design of radio telescopes such as parabolic reflectors, horn antenna, and the radio frequency interference (RFI) in the surrounding area of the National Observatory, covering the frequency band from 45 MHz to 18 GHz. The frequencies in 45–85 MHz and 120–360 MHz intervals are still relatively quiet and suitable for developing radio telescopes. The selected higher frequency of 1.4 GHz for a neutral hydrogen (HI) spectral line, 6.6 GHz for a methanol (CH3OH) spectral line, and 8.6 GHz for a helium (3 He+) spectral line is still relatively quiet and suitable for the development of radio telescopes.
{"title":"A Study for a Radio Telescope in Indonesia: Parabolic Design, Simulation of a Horn Antenna, and Radio Frequency Survey in Frequency of 0.045–18 GHz","authors":"P. Sitompul, P. Razi, T. Manik, M. Batubara, M. Lathif, Farahhati Mumtahana, R. Suryana, Ibnu Nurul Huda, Taufiq Hidayat, Yana Taryana, F. Sobirin","doi":"10.3390/aerospace11010052","DOIUrl":"https://doi.org/10.3390/aerospace11010052","url":null,"abstract":"After years of preparation, the Indonesia National Observatory, located in Mount Timau, Kupang Regency, is currently in the completion stage of research in astronomy and astrophysics and related subjects. An optic telescope with a 3.8 m diameter is expected to receive its first light in mid-2024. A feasibility study for Indonesia’s radio telescopes and networks is in progress. A single-dish parabolic radio antenna with a diameter of 20 m is proposed to work in a frequency range of 1–50 GHz. An array dipole antenna with an area of 100 m × 100 m will also be installed at a 70–350 MHz frequency. A feasibility study about system design is in progress, and a radio frequency interference (RFI) survey has been underway since 2014. In this paper, we described the design of radio telescopes such as parabolic reflectors, horn antenna, and the radio frequency interference (RFI) in the surrounding area of the National Observatory, covering the frequency band from 45 MHz to 18 GHz. The frequencies in 45–85 MHz and 120–360 MHz intervals are still relatively quiet and suitable for developing radio telescopes. The selected higher frequency of 1.4 GHz for a neutral hydrogen (HI) spectral line, 6.6 GHz for a methanol (CH3OH) spectral line, and 8.6 GHz for a helium (3 He+) spectral line is still relatively quiet and suitable for the development of radio telescopes.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"16 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139385717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.3390/aerospace11010050
Cyril Bourgenot, Valdis Krumins, David G. Bramall, Abdul M. Haque
CubeSats, known for their compact size and cost effectiveness, have gained significant popularity. However, their limited size imposes restrictions on the optical aperture and, consequently, the Ground Resolution Distance in Earth Observation missions. To overcome this limitation, the concept of deployable optical payloads with segmented primary mirrors which can unfold like petals has emerged, enabling larger synthetic apertures and enhanced spatial resolution. This study explores the potential benefits of leveraging Additive Manufacturing (AM) and Topology Optimization (TO) in the realm of ultra-precision machining, specifically single-point diamond machining. The goal is to reduce fixture weight while improving stiffness to minimize deformations caused by rotational and cutting forces which compromise optical performance. Through Finite Element Analysis, this research compares conventionally machined fixtures with those produced using AM and TO techniques. The results reveal that concept designs created via TO can achieve a remarkable 68% reduction in weight. This reduction makes the assembly, including the machining fixture and 12 U deployable segments, manageable by a single operator without the need for specialized lifting equipment. Moreover, these innovative designs lead to substantial reductions of up to 86% and 51% in deformation induced by rotational and cutting forces, respectively.
立方体卫星以体积小巧、成本效益高而著称，因此大受欢迎。然而，其有限的尺寸限制了光学孔径，从而限制了地球观测任务中的地面分辨率距离。为了克服这一限制，出现了可部署光学有效载荷的概念，这种有效载荷带有可像花瓣一样展开的分段式主镜，可实现更大的合成孔径和更高的空间分辨率。本研究探讨了在超精密加工（特别是单点金刚石加工）领域利用快速成型制造（AM）和拓扑优化（TO）的潜在优势。其目标是减轻夹具重量，同时提高刚度，以最大限度地减少旋转力和切削力造成的变形，从而降低光学性能。通过有限元分析，这项研究将传统加工夹具与使用 AM 和 TO 技术生产的夹具进行了比较。结果显示，通过 TO 技术制作的概念设计可显著减轻 68% 的重量。重量减轻后，包括加工夹具和 12 个 U 型可展开段在内的组件只需一名操作员即可操作，无需专门的起重设备。此外，这些创新设计还大大减少了旋转力和切削力引起的变形，分别高达 86% 和 51%。
{"title":"Topology Optimization of a Single-Point Diamond-Turning Fixture for a Deployable Primary Mirror Telescope","authors":"Cyril Bourgenot, Valdis Krumins, David G. Bramall, Abdul M. Haque","doi":"10.3390/aerospace11010050","DOIUrl":"https://doi.org/10.3390/aerospace11010050","url":null,"abstract":"CubeSats, known for their compact size and cost effectiveness, have gained significant popularity. However, their limited size imposes restrictions on the optical aperture and, consequently, the Ground Resolution Distance in Earth Observation missions. To overcome this limitation, the concept of deployable optical payloads with segmented primary mirrors which can unfold like petals has emerged, enabling larger synthetic apertures and enhanced spatial resolution. This study explores the potential benefits of leveraging Additive Manufacturing (AM) and Topology Optimization (TO) in the realm of ultra-precision machining, specifically single-point diamond machining. The goal is to reduce fixture weight while improving stiffness to minimize deformations caused by rotational and cutting forces which compromise optical performance. Through Finite Element Analysis, this research compares conventionally machined fixtures with those produced using AM and TO techniques. The results reveal that concept designs created via TO can achieve a remarkable 68% reduction in weight. This reduction makes the assembly, including the machining fixture and 12 U deployable segments, manageable by a single operator without the need for specialized lifting equipment. Moreover, these innovative designs lead to substantial reductions of up to 86% and 51% in deformation induced by rotational and cutting forces, respectively.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"57 42","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139384660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.3390/aerospace11010053
Yoichi Suenaga, Kojiro Suzuki
This study examines the wing hinge oscillations in an aircraft concept that employs multiple wings, or small aircraft, chained at the wing tips through freely rotatable hinges with minimal structural damping and no mechanical position-locking system. This creates a single pseudo long-span aircraft that resembles a flying chain oriented perpendicular to the flight direction. Numerical calculations were conducted using the vortex lattice method and modified equations for a multi-link rigid body pendulum. The calculations demonstrated good agreement with small-scale wind tunnel experiments, where the motion of the chained wings was tracked through color tracking, and the forces were measured using six-axis force sensors. The total CL/CD increased for the chained wings, even in the presence of hinge joint oscillations. Furthermore, numerical simulations assuming an unmanned airplane size corroborated the theoretical attainment of passive stability with high chained numbers (≥9 wings), without any structural damping and relying solely on aerodynamic forces. Guidelines for appropriate hinge axis angle δ and angle-of-attack regions for different chained wing numbers to maximize passive oscillation stability were obtained. The results showed that wing-tip-chained airplanes could successfully provide substantially large wing spans while retaining flexibility, light weight and CL/CD, without requiring active hinge rotation control.
{"title":"Coupled Aerodynamics–Structure Analysis and Wind Tunnel Experiments on Passive Hinge Oscillation of Wing-Tip-Chained Airplanes","authors":"Yoichi Suenaga, Kojiro Suzuki","doi":"10.3390/aerospace11010053","DOIUrl":"https://doi.org/10.3390/aerospace11010053","url":null,"abstract":"This study examines the wing hinge oscillations in an aircraft concept that employs multiple wings, or small aircraft, chained at the wing tips through freely rotatable hinges with minimal structural damping and no mechanical position-locking system. This creates a single pseudo long-span aircraft that resembles a flying chain oriented perpendicular to the flight direction. Numerical calculations were conducted using the vortex lattice method and modified equations for a multi-link rigid body pendulum. The calculations demonstrated good agreement with small-scale wind tunnel experiments, where the motion of the chained wings was tracked through color tracking, and the forces were measured using six-axis force sensors. The total CL/CD increased for the chained wings, even in the presence of hinge joint oscillations. Furthermore, numerical simulations assuming an unmanned airplane size corroborated the theoretical attainment of passive stability with high chained numbers (≥9 wings), without any structural damping and relying solely on aerodynamic forces. Guidelines for appropriate hinge axis angle δ and angle-of-attack regions for different chained wing numbers to maximize passive oscillation stability were obtained. The results showed that wing-tip-chained airplanes could successfully provide substantially large wing spans while retaining flexibility, light weight and CL/CD, without requiring active hinge rotation control.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"48 21","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139385130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.3390/aerospace11010049
Seyed Mohammad Hashemi, R. Botez, Georges Ghazi
Accurate aircraft trajectory prediction is fundamental for enhancing air traffic control systems, ensuring a safe and efficient aviation transportation environment. This research presents a detailed study on the efficacy of the Random Forest (RF) methodology for predicting aircraft trajectories. The study compares the RF approach with two established data-driven models, specifically Long Short-Term Memory (LSTM) and Logistic Regression (LR). The investigation utilizes a significant dataset comprising aircraft trajectory time history data, obtained from a UAS-S4 simulator. Experimental results indicate that within a short-term prediction horizon, the RF methodology surpasses both LSTM and LR in trajectory prediction accuracy and also its robustness to overfitting. The research further fine-tunes the performance of the RF methodology by optimizing various hyperparameters, including the number of estimators, features, depth, split, and leaf. Consequently, these results underscore the viability of the RF methodology as a proven alternative to LSTM and LR models for short-term aircraft trajectory prediction.
{"title":"Robust Trajectory Prediction Using Random Forest Methodology Application to UAS-S4 Ehécatl","authors":"Seyed Mohammad Hashemi, R. Botez, Georges Ghazi","doi":"10.3390/aerospace11010049","DOIUrl":"https://doi.org/10.3390/aerospace11010049","url":null,"abstract":"Accurate aircraft trajectory prediction is fundamental for enhancing air traffic control systems, ensuring a safe and efficient aviation transportation environment. This research presents a detailed study on the efficacy of the Random Forest (RF) methodology for predicting aircraft trajectories. The study compares the RF approach with two established data-driven models, specifically Long Short-Term Memory (LSTM) and Logistic Regression (LR). The investigation utilizes a significant dataset comprising aircraft trajectory time history data, obtained from a UAS-S4 simulator. Experimental results indicate that within a short-term prediction horizon, the RF methodology surpasses both LSTM and LR in trajectory prediction accuracy and also its robustness to overfitting. The research further fine-tunes the performance of the RF methodology by optimizing various hyperparameters, including the number of estimators, features, depth, split, and leaf. Consequently, these results underscore the viability of the RF methodology as a proven alternative to LSTM and LR models for short-term aircraft trajectory prediction.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"32 13","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139389750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-31DOI: 10.3390/aerospace11010047
Donghyun Kang
Despite the technological achievements of unmanned aerial vehicles (UAVs) growing in academia and industry, there is a lack of studies on the storage devices in UAVs. However, this is an important aspect because the storage devices in UAVs have a limited lifespan and performance and are rarely replaced due to a system-on-chip architecture. In this paper, we study how UAVs impact the lifespan and performance of the underlying storage device while capturing images during overflight. We also propose a new lifespan and performance-saving mechanism, called Delay-D, which is designed at the kernel level to efficiently utilize the features of NAND flash-based storage devices. To confirm the effectiveness of Delay-D, we implement a simulator that replays realistic write patterns on UAVs and evaluate quantitative experiments in two different experimental environments. In our evaluation, Delay-D demonstrates the dramatic extension possibility of the lifespan by reducing the number of extra writes inside the storage device and improving the overall performance by up to 2.1× on the commercial NVMe SSD.
{"title":"Delay-D: Research on the Lifespan and Performance of Storage Devices in Unmanned Aerial Vehicles","authors":"Donghyun Kang","doi":"10.3390/aerospace11010047","DOIUrl":"https://doi.org/10.3390/aerospace11010047","url":null,"abstract":"Despite the technological achievements of unmanned aerial vehicles (UAVs) growing in academia and industry, there is a lack of studies on the storage devices in UAVs. However, this is an important aspect because the storage devices in UAVs have a limited lifespan and performance and are rarely replaced due to a system-on-chip architecture. In this paper, we study how UAVs impact the lifespan and performance of the underlying storage device while capturing images during overflight. We also propose a new lifespan and performance-saving mechanism, called Delay-D, which is designed at the kernel level to efficiently utilize the features of NAND flash-based storage devices. To confirm the effectiveness of Delay-D, we implement a simulator that replays realistic write patterns on UAVs and evaluate quantitative experiments in two different experimental environments. In our evaluation, Delay-D demonstrates the dramatic extension possibility of the lifespan by reducing the number of extra writes inside the storage device and improving the overall performance by up to 2.1× on the commercial NVMe SSD.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"81 16","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139132153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-31DOI: 10.3390/aerospace11010048
Saile Zhang, Qingzhen Yang, Rui Wang, Xufei Wang
The use of traditional optimization methods in engineering design problems, specifically in aerodynamic and infrared stealth optimization for engine nozzles, requires a large number of objective function evaluations, therefore introducing a considerable challenge in terms of time constraints. In this paper, this limitation is addressed by using a sample-efficient multi-objective Bayesian optimization that takes Kriging as a surrogate model and Expected Hypervolume Improvement as the infill criterion. Using this approach, the probabilistic model is continuously established and updated, and the approximate Pareto front is obtained at a relatively small computational budget. The objective of this work is to evaluate the applicability of employing a multi-objective Bayesian optimization framework for the aerodynamic-infrared shape optimization of an elliptical double serpentine nozzle at 6 km flight condition, where the objective functions are evaluated by means of high-fidelity computational fluid dynamics and reversed Monte Carlo ray tracing simulations. We achieve good results in both infrared radiation signature reduction and aerodynamic performance improvement with a reasonable number of evaluations, indicating that the proposed method is effective and efficient for tackling the computationally intensive optimization challenges in the aircraft design.
{"title":"Multi-Objective Bayesian Optimization Design of Elliptical Double Serpentine Nozzle","authors":"Saile Zhang, Qingzhen Yang, Rui Wang, Xufei Wang","doi":"10.3390/aerospace11010048","DOIUrl":"https://doi.org/10.3390/aerospace11010048","url":null,"abstract":"The use of traditional optimization methods in engineering design problems, specifically in aerodynamic and infrared stealth optimization for engine nozzles, requires a large number of objective function evaluations, therefore introducing a considerable challenge in terms of time constraints. In this paper, this limitation is addressed by using a sample-efficient multi-objective Bayesian optimization that takes Kriging as a surrogate model and Expected Hypervolume Improvement as the infill criterion. Using this approach, the probabilistic model is continuously established and updated, and the approximate Pareto front is obtained at a relatively small computational budget. The objective of this work is to evaluate the applicability of employing a multi-objective Bayesian optimization framework for the aerodynamic-infrared shape optimization of an elliptical double serpentine nozzle at 6 km flight condition, where the objective functions are evaluated by means of high-fidelity computational fluid dynamics and reversed Monte Carlo ray tracing simulations. We achieve good results in both infrared radiation signature reduction and aerodynamic performance improvement with a reasonable number of evaluations, indicating that the proposed method is effective and efficient for tackling the computationally intensive optimization challenges in the aircraft design.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"103 32","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139133547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-31DOI: 10.3390/aerospace11010046
Ming Qi, Wenguo Zhu, Shu Li
The flight of a migratory bird-like flapping-wing aircraft is characterized by a low Reynolds number and unsteadiness. The selection of airfoil profiles is critical to designing an efficient flapping-wing aircraft. To choose the suitable airfoil for various wing sections, it is necessary to calculate the aerodynamic forces of the unsteady two-dimensional airfoil with a Reynolds number in the range of 105. While accurate, calculating this by solving the Navier–Stokes equations is impractical for early design stages due to its high consumption of computing resources and time. The computational demands for extending it to 3D aerodynamic calculations are even more prohibitive. In this paper, a relatively simple method is proposed. The two-dimensional unsteady panel method is utilized to derive the inviscid flow field, the unsteady integral boundary layer method is utilized to solve the boundary layer viscous flow, and the eN transition model is adopted to predict the position of the transition. These models are coupled with the semi-inverse interaction method to solve the aerodynamics of the unsteady low-Reynolds-number two-dimensional airfoil. The unsteady aerodynamics of the symmetric and cambered airfoils at different wing sections are calculated respectively by the proposed method. Mechanism analysis of the calculation results is conducted, and a symmetrical airfoil or a slightly cambered airfoil is recommended for the wing tip, a moderately cambered airfoil is suggested for the outer-wing section, and a highly cambered airfoil is suggested for the inner-wing section.
候鸟式拍翼飞机的飞行特点是雷诺数低和不稳定。机翼轮廓的选择对于设计高效的拍翼飞机至关重要。要为不同翼段选择合适的翼面，必须计算雷诺数在 105 范围内的二维非稳定翼面的气动力。通过求解纳维-斯托克斯方程进行计算虽然准确，但由于需要消耗大量计算资源和时间，因此在早期设计阶段并不实用。将其扩展到三维空气动力学计算所需的计算资源甚至更多。本文提出了一种相对简单的方法。利用二维非稳态面板法推导无粘性流场，利用非稳态积分边界层法求解边界层粘性流，并采用 eN 过渡模型预测过渡位置。这些模型与半逆向相互作用方法相结合，求解了低雷诺数二维机翼的非稳态空气动力学。利用所提出的方法分别计算了对称翼面和外凸翼面在不同翼面截面上的非稳态空气动力学。对计算结果进行了机理分析，建议翼尖采用对称翼面或轻度外倾翼面，翼外段采用中度外倾翼面，翼内段采用高度外倾翼面。
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Pub Date : 2023-12-31DOI: 10.3390/aerospace11010045
Radvan Bahbouh, Eva Hoschlova, Michal Huzva, Katerina Bernardova Sykorova
(1) Background: Starting in 1993, the sociomapping method was used in the Czech Army to map communication. After initial pilot tests in military aviation, where we verified the reliability and validity of the basic subjective scales (for example, by correlations with physiological data), this method was utilized for communication mapping in the HUBES (Human Behavior in Extended Spaceflight) experiment conducted between 1994 and 1995, and since then has been repeatedly used in experiments simulating long-term space flights. (2) Methods: In this article, we summarize the key findings obtained through sociomapping in eight space experiments with crews including women, conducted between 2015 and 2023, including five experiments at the Mars Desert Research Station (MDRS) and in three stages of the SIRIUS project (Scientific International Research in Unique Terrestrial Station). (3) Results: The median test-retest correlation for both the frequency and quality of communication was 0.64, ranging widely from −0.74 to 1. The quantity and quality of communication showed a moderately strong correlation (0.40). Control charts demonstrated diverse developmental trends in crew communication across the experiments. Sociomapping allowed for more detailed visualization of the structure and dynamics of communication throughout the missions, as well as the detection of subgrouping and isolation of individuals in the crews. (4) Conclusions: The experiments showed that scaled assessments of mutual communication in terms of both quantity (frequency) and quality are a reliable and valid tool that enables the capture of significant one-time fluctuations and/or long-term trends. The experiments highlighted the possibility of increased risk of significant fluctuations and gradual deterioration of communication in the second half of the mission, which, however, does not have to be the rule, especially in shorter isolations. Continuous monitoring of communication through simple rating scales allows for timely intervention and stabilization of communication.
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