Given the harsh operating circumstances, hypersonic vehicles operating at high Mach number demand accurate advanced information of the flight and health state. Flight parameter prediction is a crucial foundation for achieving this requirement. This work addressed the trade-off between prediction accuracy and efficiency by proposing a flight parameter prediction model with the model pre-training and online parameter updating. To create training data, a mechanism model is established. Then, we construct and evaluate three distinct prediction models to increase prediction accuracy. Finally, we conducted comparative validation experiments to compare the prediction performance of the three models. The findings demonstrate that the suggested model greatly raises prediction accuracy without raising model complexity, better balancing prediction accuracy and efficiency. The prediction accuracy of the suggested model has increased by 81.9% when compared to the traditional model.
{"title":"Flight parameter prediction for high-dynamic Hypersonic vehicle system based on pre-training machine learning model","authors":"Dengji Zhou, Dawen Huang, Xing Zhang, Ming Tie, Yulin Wang, Yaoxin Shen","doi":"10.1177/09544100231209014","DOIUrl":"https://doi.org/10.1177/09544100231209014","url":null,"abstract":"Given the harsh operating circumstances, hypersonic vehicles operating at high Mach number demand accurate advanced information of the flight and health state. Flight parameter prediction is a crucial foundation for achieving this requirement. This work addressed the trade-off between prediction accuracy and efficiency by proposing a flight parameter prediction model with the model pre-training and online parameter updating. To create training data, a mechanism model is established. Then, we construct and evaluate three distinct prediction models to increase prediction accuracy. Finally, we conducted comparative validation experiments to compare the prediction performance of the three models. The findings demonstrate that the suggested model greatly raises prediction accuracy without raising model complexity, better balancing prediction accuracy and efficiency. The prediction accuracy of the suggested model has increased by 81.9% when compared to the traditional model.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141344909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1177/09544100241260108
Bhushan Dewangan, H. Roy
To achieve an aerodynamically efficient design of fuselage for bioinspired unmanned aerial vehicles (UAV), the development of a systematic method is of paramount need. This work presents a multiobjective optimization study for shape parameterization of a 2D fuselage of foldable flapping wing UAV in low Reynolds number (2e05) flight conditions. The novelty of the research work lies in integrating S1223 airfoil characteristics for predicting the efficient shape design of the fuselage. This paper offers four sections; (i) the validation of the ANSYS Fluent model with experiment, (ii) the exploration of design variables using Design of Experiment (Sparse Grid Initialization), (iii) the implementation of response surface method (Genetic Aggregation) to know about dimensional sensitivity among independent and dependent variables and (iv) the application of multiobjective optimization method i.e. NSGA II to optimize the drag and lift coefficient. To identify the superiority, a comparative study between the original and optimized fuselage is presented considering many parameters like pressure contours, velocity contours, pressure coefficients, and streamlines representations. It is evident from various results that the 2D optimum shape significantly minimizes the drag coefficient and increases the lift coefficient. This work also makes room for 3D shape optimization, which helps in prototype fabrication for real-time flight conditions.
{"title":"Numerical two-dimensional optimization of a cylindrical fuselage for bioinspired unmanned aerial vehicle based on non-dominated sorting genetic algorithm-II","authors":"Bhushan Dewangan, H. Roy","doi":"10.1177/09544100241260108","DOIUrl":"https://doi.org/10.1177/09544100241260108","url":null,"abstract":"To achieve an aerodynamically efficient design of fuselage for bioinspired unmanned aerial vehicles (UAV), the development of a systematic method is of paramount need. This work presents a multiobjective optimization study for shape parameterization of a 2D fuselage of foldable flapping wing UAV in low Reynolds number (2e05) flight conditions. The novelty of the research work lies in integrating S1223 airfoil characteristics for predicting the efficient shape design of the fuselage. This paper offers four sections; (i) the validation of the ANSYS Fluent model with experiment, (ii) the exploration of design variables using Design of Experiment (Sparse Grid Initialization), (iii) the implementation of response surface method (Genetic Aggregation) to know about dimensional sensitivity among independent and dependent variables and (iv) the application of multiobjective optimization method i.e. NSGA II to optimize the drag and lift coefficient. To identify the superiority, a comparative study between the original and optimized fuselage is presented considering many parameters like pressure contours, velocity contours, pressure coefficients, and streamlines representations. It is evident from various results that the 2D optimum shape significantly minimizes the drag coefficient and increases the lift coefficient. This work also makes room for 3D shape optimization, which helps in prototype fabrication for real-time flight conditions.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141362297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-07DOI: 10.1177/09544100241260086
Yuan-wen Zhang, Tian Ma
Orbital debris with equivalent size of 1∼10 cm is hard to be detected and its number is huge, which is the most harmful to on-orbit spacecraft while there is still no effective removal means. Inspired by vacuum cleaner, applying the conductive property of orbital debris and the physical law that variable magnetic flux would induce eddy current on the surface of a conductive material, this paper put forward a novel approach of ‘along orbit debris self-collecting with rotating constant magnetic dipole array’. Based on dynamic modeling, self-collecting feasibility and control capability analysis, evolution law of relative orbital motion with induced magnetic force derivation, and on-orbit debris magnetic collecting numerical simulation, this novel approach has been verified and the corresponding requirements of magnetic collector are put forward. In addition, this paper also gave how to use several key parameters to adjust the region of along orbit debris self-collecting, and pointed out several problems needing to be researched in-depth for actual application.
{"title":"Dynamics and capability of along orbit debris self-collecting with rotating constant magnets","authors":"Yuan-wen Zhang, Tian Ma","doi":"10.1177/09544100241260086","DOIUrl":"https://doi.org/10.1177/09544100241260086","url":null,"abstract":"Orbital debris with equivalent size of 1∼10 cm is hard to be detected and its number is huge, which is the most harmful to on-orbit spacecraft while there is still no effective removal means. Inspired by vacuum cleaner, applying the conductive property of orbital debris and the physical law that variable magnetic flux would induce eddy current on the surface of a conductive material, this paper put forward a novel approach of ‘along orbit debris self-collecting with rotating constant magnetic dipole array’. Based on dynamic modeling, self-collecting feasibility and control capability analysis, evolution law of relative orbital motion with induced magnetic force derivation, and on-orbit debris magnetic collecting numerical simulation, this novel approach has been verified and the corresponding requirements of magnetic collector are put forward. In addition, this paper also gave how to use several key parameters to adjust the region of along orbit debris self-collecting, and pointed out several problems needing to be researched in-depth for actual application.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141371811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-07DOI: 10.1177/09544100241260101
Siwei Wang, Yangang Wang, Fang Zhou, Yue Xv
The unsteady numerical analysis method was utilized to investigate the unsteady flow structure of a contra-rotating ducted fan under crosswind conditions. The development and evolution mechanism of the lip vortex under the combined action of crosswind and rotor were studied. Two perspectives, namely the time-averaged flow field and unsteady time-frequency analysis, were employed for the examination. The results indicate that the unsteady aerodynamic forces exerted on the lip of the ducted fan are primarily influenced by four sets of frequencies, ranked in descending order of magnitude: 1 BPF (Blade Passing Frequency) of the upstream rotor, 1 BPF of the downstream rotor, the combined effect of the 1 BPF of the upstream rotor and 1 BPF of the downstream rotor, and 2 BPF of the upstream rotor. The maximum velocity occurs at the position where the inner surface of the windward side lip is inclined 40° from the freestream velocity direction, and a stable separation vortex is formed below this region. The lip separation vortex triggers the generation of blade suction side separation vortex in the upstream rotor, and its periodic formation, growth, shedding, and dissipation are the primary factors contributing to the unsteady flow. The research findings lay the groundwork for further advancements in active and passive flow control technologies under crosswind conditions.
{"title":"Investigating the unsteady flow mechanism at the lip of a ducted fan in crosswind","authors":"Siwei Wang, Yangang Wang, Fang Zhou, Yue Xv","doi":"10.1177/09544100241260101","DOIUrl":"https://doi.org/10.1177/09544100241260101","url":null,"abstract":"The unsteady numerical analysis method was utilized to investigate the unsteady flow structure of a contra-rotating ducted fan under crosswind conditions. The development and evolution mechanism of the lip vortex under the combined action of crosswind and rotor were studied. Two perspectives, namely the time-averaged flow field and unsteady time-frequency analysis, were employed for the examination. The results indicate that the unsteady aerodynamic forces exerted on the lip of the ducted fan are primarily influenced by four sets of frequencies, ranked in descending order of magnitude: 1 BPF (Blade Passing Frequency) of the upstream rotor, 1 BPF of the downstream rotor, the combined effect of the 1 BPF of the upstream rotor and 1 BPF of the downstream rotor, and 2 BPF of the upstream rotor. The maximum velocity occurs at the position where the inner surface of the windward side lip is inclined 40° from the freestream velocity direction, and a stable separation vortex is formed below this region. The lip separation vortex triggers the generation of blade suction side separation vortex in the upstream rotor, and its periodic formation, growth, shedding, and dissipation are the primary factors contributing to the unsteady flow. The research findings lay the groundwork for further advancements in active and passive flow control technologies under crosswind conditions.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141372702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-03DOI: 10.1177/09544100241257292
Abhijeet Abhijeet, Tanya K Kumar, D. Giri
This paper presents a novel strategy for decoupling the attitude and orbit equations of a CubeSat for rendezvous and docking with an uncontrollable cooperative target. For computing a safe trajectory, the proposed control algorithm takes into account the solar energy received by the CubeSat. The CubeSat is equipped with a thruster for orbit maneuvers, magnetic coils for attitude control, and four fixed single-sided rectangular solar panels. The coupled dynamics arising from the dynamical model of the spacecraft is solved using a novel weighted vector-based approach. This paper presents a linearized nonlinear optimal control problem arising in small spacecrafts while trying to maximize solar energy input in the rendezvous and docking process. An intermediate orbit is defined and used to divide the problem into two different optimal control problems: rendezvous optimization and docking optimization problems. A geometrical approach based on the shape of the chaser and the target is contemplated for collision avoidance while docking. The proposed controller design is modified whenever the sunlight is obstructed by the Earth, and the maneuvering controls are redesigned accordingly for optimal rendezvous and docking. Numerical simulations have been carried out to show the efficacy of the proposed concept for steering the trade-off between solar energy and control input during the rendezvous and docking of CubeSat with a tumbling target.
{"title":"Control strategy for trading off solar power and control input while rendezvous and docking","authors":"Abhijeet Abhijeet, Tanya K Kumar, D. Giri","doi":"10.1177/09544100241257292","DOIUrl":"https://doi.org/10.1177/09544100241257292","url":null,"abstract":"This paper presents a novel strategy for decoupling the attitude and orbit equations of a CubeSat for rendezvous and docking with an uncontrollable cooperative target. For computing a safe trajectory, the proposed control algorithm takes into account the solar energy received by the CubeSat. The CubeSat is equipped with a thruster for orbit maneuvers, magnetic coils for attitude control, and four fixed single-sided rectangular solar panels. The coupled dynamics arising from the dynamical model of the spacecraft is solved using a novel weighted vector-based approach. This paper presents a linearized nonlinear optimal control problem arising in small spacecrafts while trying to maximize solar energy input in the rendezvous and docking process. An intermediate orbit is defined and used to divide the problem into two different optimal control problems: rendezvous optimization and docking optimization problems. A geometrical approach based on the shape of the chaser and the target is contemplated for collision avoidance while docking. The proposed controller design is modified whenever the sunlight is obstructed by the Earth, and the maneuvering controls are redesigned accordingly for optimal rendezvous and docking. Numerical simulations have been carried out to show the efficacy of the proposed concept for steering the trade-off between solar energy and control input during the rendezvous and docking of CubeSat with a tumbling target.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141272238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-24DOI: 10.1177/09544100241254411
Madhumita Pal
A finite-time consensus protocol is presented in this paper for a network of connected heterogeneous agents with fixed and switching topology. In this study, two cases directed networks with fixed topology and directed networks with switching topology are examined. Convergence analysis for both the cases are presented. An independent tracking controller, which assures that an agent follows an ideal trajectory designed by sliding mode based consensus control, is devised. Agents stability are independent of the distributed consensus algorithm. Under the proposed control methodology, the measurement vectors of heterogeneous agents converge to the agreement value in a finite amount of time. The comparison results with the existing works show the proposed algorithm’s improved performance in terms of convergence time in presence of disturbances.
{"title":"Finite-time consensus of heterogeneous unmanned aerial agents in network with fixed and switching topology","authors":"Madhumita Pal","doi":"10.1177/09544100241254411","DOIUrl":"https://doi.org/10.1177/09544100241254411","url":null,"abstract":"A finite-time consensus protocol is presented in this paper for a network of connected heterogeneous agents with fixed and switching topology. In this study, two cases directed networks with fixed topology and directed networks with switching topology are examined. Convergence analysis for both the cases are presented. An independent tracking controller, which assures that an agent follows an ideal trajectory designed by sliding mode based consensus control, is devised. Agents stability are independent of the distributed consensus algorithm. Under the proposed control methodology, the measurement vectors of heterogeneous agents converge to the agreement value in a finite amount of time. The comparison results with the existing works show the proposed algorithm’s improved performance in terms of convergence time in presence of disturbances.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141100735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-22DOI: 10.1177/09544100241253317
Xianzhe Cheng, K. Lv, Yong Zhang, Wenxiang Yang, Lei Wang, Weihu Zhao, Guanjun Liu, Jing Qiu
Intermittent faults are widely present in aviation electronic devices, especially in various electrical connectors. It is usually hard to diagnose the source of the intermittent faults, which brings a huge challenge to the repair and maintenance of equipment. This paper focuses on the intermittent faults in typical aviation electrical connectors activated by shock test. The transient arc wave is observed on a nanosecond scale during the occurrence of the intermittent faults. An arc signal model is constructed to analyze the impact factors of the signal. Based on the arc wave characteristics, further intermittent fault diagnostic analyses are conducted on four types of connector components: damaged solder joints, cracked pin connections, loose wire connections and worn electrical connectors. The effective arc wave components of the raw signals are extracted using Variational Mode Decomposition (VMD), and a comparison is made between traditional diagnostic method and CNN-based deep learning method. The results show that the combination of VMD-CNN-SVM achieves the optimal diagnostic effect. The diagnostic results reflect that the proposed arc signal features are suitable for diagnosing intermittent faults in connector components.
{"title":"Intermittent fault diagnosis in connector components based on arc wave characteristics","authors":"Xianzhe Cheng, K. Lv, Yong Zhang, Wenxiang Yang, Lei Wang, Weihu Zhao, Guanjun Liu, Jing Qiu","doi":"10.1177/09544100241253317","DOIUrl":"https://doi.org/10.1177/09544100241253317","url":null,"abstract":"Intermittent faults are widely present in aviation electronic devices, especially in various electrical connectors. It is usually hard to diagnose the source of the intermittent faults, which brings a huge challenge to the repair and maintenance of equipment. This paper focuses on the intermittent faults in typical aviation electrical connectors activated by shock test. The transient arc wave is observed on a nanosecond scale during the occurrence of the intermittent faults. An arc signal model is constructed to analyze the impact factors of the signal. Based on the arc wave characteristics, further intermittent fault diagnostic analyses are conducted on four types of connector components: damaged solder joints, cracked pin connections, loose wire connections and worn electrical connectors. The effective arc wave components of the raw signals are extracted using Variational Mode Decomposition (VMD), and a comparison is made between traditional diagnostic method and CNN-based deep learning method. The results show that the combination of VMD-CNN-SVM achieves the optimal diagnostic effect. The diagnostic results reflect that the proposed arc signal features are suitable for diagnosing intermittent faults in connector components.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141110874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To investigate the effects and mechanisms of rotor open crack on axial compressor performance, a steady 3D single-passage numerical simulation is used on NASA Stage 35. The results show that the crack leakage flow can affect the compressor performance, and the crack at the middle span has the most serious effect. At 100% rotating speed, there is a 1.2% decrease in peak total pressure ratio and a 0.36% decrease in peak efficiency. Besides, the stability margin is reduced by 26.9% relatively. The effect of crack is not only limited to the span range near it, and the main phenomena of cracks at different spans are various, concentrating in the aspects of vortex structure and stator passage flow. From peak efficiency to near stall condition, the effect of crack leakage flow is gradually strengthened, which leads to the flow blockage and reduces the working flow range of compressor. With the decrement of rotating speed, the reduction of stability margin increases gradually, but the influence span range of crack at low-speed narrows.
为了研究转子开裂对轴流压缩机性能的影响和机理，对 NASA Stage 35 进行了稳定的三维单通道数值模拟。结果表明，裂缝泄漏流会影响压缩机的性能，而中间跨度的裂缝影响最为严重。在 100% 转速下，峰值总压比下降 1.2%，峰值效率下降 0.36%。此外，稳定裕度也相对减少了 26.9%。裂纹的影响不仅限于裂纹附近的跨度范围，不同跨度裂纹的主要现象也多种多样，主要集中在涡流结构和定子通道流动方面。从峰值效率到接近失速状态，裂纹泄漏流的影响逐渐加强，导致流量堵塞，缩小了压缩机的工作流量范围。随着转速的降低，稳定性裕度的减小逐渐增大，但低速时裂纹的影响范围缩小。
{"title":"Effect of open crack on axial compressor performance","authors":"Zhongyi Wang, Tianchu Song, Yanhua Wang, Zheng Li, Shuguang Chu","doi":"10.1177/09544100241252230","DOIUrl":"https://doi.org/10.1177/09544100241252230","url":null,"abstract":"To investigate the effects and mechanisms of rotor open crack on axial compressor performance, a steady 3D single-passage numerical simulation is used on NASA Stage 35. The results show that the crack leakage flow can affect the compressor performance, and the crack at the middle span has the most serious effect. At 100% rotating speed, there is a 1.2% decrease in peak total pressure ratio and a 0.36% decrease in peak efficiency. Besides, the stability margin is reduced by 26.9% relatively. The effect of crack is not only limited to the span range near it, and the main phenomena of cracks at different spans are various, concentrating in the aspects of vortex structure and stator passage flow. From peak efficiency to near stall condition, the effect of crack leakage flow is gradually strengthened, which leads to the flow blockage and reduces the working flow range of compressor. With the decrement of rotating speed, the reduction of stability margin increases gradually, but the influence span range of crack at low-speed narrows.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140964009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-10DOI: 10.11606/t.18.2023.tde-24112023-100910
Maliheh Najafi, António J. M. Ferreira, Flávio D. Marques
Sandwich structures with lattice cores are novel, lightweight composite structures and are widely used in the aerospace industry. Besides, the aeroelastic behavior of sandwich panels in a supersonic flow regime still needs to be thoroughly studied. This work investigates the supersonic flutter of a sandwich panel whose core is topology-optimized. A finite element model of a sandwich panel based on the layerwise theory, coupled with the first-order piston theory, is presented. The sandwich panel core is assessed using a topology optimization approach with flutter loading constraints. The subsequent analytical homogenization scheme is developed to provide the equivalent mechanical properties of the topology-optimized panel. The modeling approach is fully validated, and the results demonstrate that the sandwich panel is capable of enlarging the flutter-free operational flight range when compared with other conventional panel designs. A parametric analysis of the topology-optimized sandwich panel regarding the critical flutter conditions is performed.
{"title":"Aeroelastic analysis of a lightweight topology-optimized sandwich panel","authors":"Maliheh Najafi, António J. M. Ferreira, Flávio D. Marques","doi":"10.11606/t.18.2023.tde-24112023-100910","DOIUrl":"https://doi.org/10.11606/t.18.2023.tde-24112023-100910","url":null,"abstract":"Sandwich structures with lattice cores are novel, lightweight composite structures and are widely used in the aerospace industry. Besides, the aeroelastic behavior of sandwich panels in a supersonic flow regime still needs to be thoroughly studied. This work investigates the supersonic flutter of a sandwich panel whose core is topology-optimized. A finite element model of a sandwich panel based on the layerwise theory, coupled with the first-order piston theory, is presented. The sandwich panel core is assessed using a topology optimization approach with flutter loading constraints. The subsequent analytical homogenization scheme is developed to provide the equivalent mechanical properties of the topology-optimized panel. The modeling approach is fully validated, and the results demonstrate that the sandwich panel is capable of enlarging the flutter-free operational flight range when compared with other conventional panel designs. A parametric analysis of the topology-optimized sandwich panel regarding the critical flutter conditions is performed.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140991669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study proposes a fault diagnosis method based on a time-variable transformer network for satellite attitude control system telemetry data, which has the properties of a time series and strong multivariate correlation. First, a time-attention module was utilised to determine the correlation between the data at a specific time and before that time to effectively identify the dynamic properties of the data. A variable attention module is introduced to capture the degree of correlation between various variables to achieve multivariate decoupling. Then, the interactive attention layer combines the dynamic properties of the data with the correlations between the variables to achieve dynamic data decorrelation. Finally, a linear layer is used to implement the fault diagnosis.
{"title":"Improved time-variable transformer-based fault diagnosis method for satellite attitude control system","authors":"Wei Zhang, Sida Chen, Sheng Gao, Zhaoguang Wang, Qinkun Cheng","doi":"10.1177/09544100241248732","DOIUrl":"https://doi.org/10.1177/09544100241248732","url":null,"abstract":"This study proposes a fault diagnosis method based on a time-variable transformer network for satellite attitude control system telemetry data, which has the properties of a time series and strong multivariate correlation. First, a time-attention module was utilised to determine the correlation between the data at a specific time and before that time to effectively identify the dynamic properties of the data. A variable attention module is introduced to capture the degree of correlation between various variables to achieve multivariate decoupling. Then, the interactive attention layer combines the dynamic properties of the data with the correlations between the variables to achieve dynamic data decorrelation. Finally, a linear layer is used to implement the fault diagnosis.","PeriodicalId":506990,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140659620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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