Pub Date : 2021-05-10DOI: 10.4050/f-0077-2021-16870
M. Sugiura, Akira Yoshida, Takuya Furumoto, Kuniyuki Takekawa, K. Kimura, N. Kobiki, H. Sugawara, Y. Tanabe, Yoshiki Iwasaki, Takahiro Noda, Y. Shibata, Tomoka Tsujiuchi, Kentaro Ueda, Hidemasa Yasuda
Aerodynamic characteristics of optimized blade tip geometries for flight at high advance ratio are identified by wind tunnel tests conducted in October 2020. Several types of high-speed compound helicopters are in the development process today after the successful technology demonstrations. JAXA has been studying a high-speed compound helicopter for emergency medical service since it is expected to help save lives significantly in Japan. In this study, optimized blade shapes are invented, whose high-speed performance is twice as high as a conventional blade shape while maintaining hovering performance. In this paper, an optimized rotor blade with a swept-back angle is evaluated highest among optimized rotors and UH-60A rotor in the items of hover performance, high-speed performance, reduction effect of rotor drive power, control hydraulic system output reduction effect, and static aerodynamic stability. Thus, it is concluded that an optimized rotor blade with a swept-back angle is the most practical from the viewpoint of the aerodynamic characteristics of the rotor blade tips.
{"title":"Wind Tunnel Test of Optimal Rotor Blade Tip for a Winged Compound Helicopter at High Advance Ratio","authors":"M. Sugiura, Akira Yoshida, Takuya Furumoto, Kuniyuki Takekawa, K. Kimura, N. Kobiki, H. Sugawara, Y. Tanabe, Yoshiki Iwasaki, Takahiro Noda, Y. Shibata, Tomoka Tsujiuchi, Kentaro Ueda, Hidemasa Yasuda","doi":"10.4050/f-0077-2021-16870","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16870","url":null,"abstract":"\u0000 Aerodynamic characteristics of optimized blade tip geometries for flight at high advance ratio are identified by wind tunnel tests conducted in October 2020. Several types of high-speed compound helicopters are in the development process today after the successful technology demonstrations. JAXA has been studying a high-speed compound helicopter for emergency medical service since it is expected to help save lives significantly in Japan. In this study, optimized blade shapes are invented, whose high-speed performance is twice as high as a conventional blade shape while maintaining hovering performance. In this paper, an optimized rotor blade with a swept-back angle is evaluated highest among optimized rotors and UH-60A rotor in the items of hover performance, high-speed performance, reduction effect of rotor drive power, control hydraulic system output reduction effect, and static aerodynamic stability. Thus, it is concluded that an optimized rotor blade with a swept-back angle is the most practical from the viewpoint of the aerodynamic characteristics of the rotor blade tips.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130411275","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16838
Johannes Hofmann, M. Mindt, Felix Weiss
A new comprehensive aeromechanics code for rotary wing aircraft is being developed at the German Aerospace Center. It follows a new and very general approach in modeling all physical subsystems and numerical methods in one common interface description. The structure of the code makes no assumptions about the system to be modeled and builds the global system strictly from the logical connections of the sub-models. It relies heavily on modern language features and programming techniques like algorithmic differentiation. This paper describes the novel approach and currently implemented features. While verification and validation are a part of the paper it is not the sole purpose. The calculations serve rather as a means of verifying the general approach and its fitness for the long-term vision of the code. The description of the architectural concept is the main purpose of this paper. The description and evaluation is being underlined with a set of verification and preliminary validation cases.
{"title":"A New Approach to Comprehensive Rotorcraft Aeromechanics Simulation","authors":"Johannes Hofmann, M. Mindt, Felix Weiss","doi":"10.4050/f-0077-2021-16838","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16838","url":null,"abstract":"\u0000 A new comprehensive aeromechanics code for rotary wing aircraft is being developed at the German Aerospace Center. It follows a new and very general approach in modeling all physical subsystems and numerical methods in one common interface description. The structure of the code makes no assumptions about the system to be modeled and builds the global system strictly from the logical connections of the sub-models. It relies heavily on modern language features and programming techniques like algorithmic differentiation. This paper describes the novel approach and currently implemented features. While verification and validation are a part of the paper it is not the sole purpose. The calculations serve rather as a means of verifying the general approach and its fitness for the long-term vision of the code. The description of the architectural concept is the main purpose of this paper. The description and evaluation is being underlined with a set of verification and preliminary validation cases.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125728770","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16897
J. Lua, Ethan Fulghum, Xiaodong Cui, Jian Xiao, S. Kariyawasam, C. Saathoff
This paper presents the characterization of bearing failure mechanisms in composite joints with countersunk bolt by applying an X-ray Computed Tomography (XCT) technique and a developed bearing failure model to build the physical mechanisms into the framework of continuum damage mechanics (CDM) in our composite bolted and bonded analysis tool for Abaqus (CB2ATA). The high-fidelity XCT was explored for the detection and characterization of bearing failure in bolted composite components without removing the fastener, which could introduce significant scatter in XCT scan due to its high density, compared with lightweight carbon fiber reinforced polymer (CFRP) composite laminates. A static bearing model was also developed for the damaged material response in the bearing region based on a micromechanics analysis in the longitudinal and transverse directions. In this study, single shear bearing (SSB) tests was firstly executed with XCT scan, and then progressive failure analyses were performed to explore the effects of bolt failure on the interaction of the intra- and inter-ply damages. The predicted load-displacement response was compared with experimental measurement, and the simulated failure patterns were compared with the XCT images. A new design was proposed using the enhanced analysis tool to achieve a dominant bearing failure mechanism on the basis of the current SSB test.
{"title":"A Combined X-Ray CT and Mechanistic Characterization of Bearing Failure Mechanisms in Bolted Composite Components","authors":"J. Lua, Ethan Fulghum, Xiaodong Cui, Jian Xiao, S. Kariyawasam, C. Saathoff","doi":"10.4050/f-0077-2021-16897","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16897","url":null,"abstract":"\u0000 This paper presents the characterization of bearing failure mechanisms in composite joints with countersunk bolt by applying an X-ray Computed Tomography (XCT) technique and a developed bearing failure model to build the physical mechanisms into the framework of continuum damage mechanics (CDM) in our composite bolted and bonded analysis tool for Abaqus (CB2ATA). The high-fidelity XCT was explored for the detection and characterization of bearing failure in bolted composite components without removing the fastener, which could introduce significant scatter in XCT scan due to its high density, compared with lightweight carbon fiber reinforced polymer (CFRP) composite laminates. A static bearing model was also developed for the damaged material response in the bearing region based on a micromechanics analysis in the longitudinal and transverse directions. In this study, single shear bearing (SSB) tests was firstly executed with XCT scan, and then progressive failure analyses were performed to explore the effects of bolt failure on the interaction of the intra- and inter-ply damages. The predicted load-displacement response was compared with experimental measurement, and the simulated failure patterns were compared with the XCT images. A new design was proposed using the enhanced analysis tool to achieve a dominant bearing failure mechanism on the basis of the current SSB test.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126035979","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16903
Chen He, E. Bae, Tzikang Chen, Dooyong Lee, M. Haile
Rotorcraft experience vibratory loads due to the constantly varying airloads under all flight conditions. Maximizing the fatigue life of their structural components is a vital factor for sustained operations with low-maintenance. Most existing fatigue analysis methods are empirical and, hence, are limited for use in investigating the effects of maneuvering f light as well as for exploring modern control methods (e.g., on-blade controls (OBC)) for alleviating fatigue. This paper discusses comprehensive simulation-based rotorcraft loads/stress analysis and fatigue alleviation control methods toward the goal of minimum maintenance for future vertical lift. The paper covers several aspects, including comprehensive modeling for loads prediction, blade stress analysis with the applied loads, fatigue estimation, and loads/stress reduction control formulation. The paper also presents simulation results that demonstrate the successful reduction of vibratory loads/stress using modern on-blade active control methods.
{"title":"Comprehensive Simulation Based Rotorcraft Loads/Fatigue Analysis and Alleviation Method","authors":"Chen He, E. Bae, Tzikang Chen, Dooyong Lee, M. Haile","doi":"10.4050/f-0077-2021-16903","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16903","url":null,"abstract":"\u0000 Rotorcraft experience vibratory loads due to the constantly varying airloads under all flight conditions. Maximizing the fatigue life of their structural components is a vital factor for sustained operations with low-maintenance. Most existing fatigue analysis methods are empirical and, hence, are limited for use in investigating the effects of maneuvering f light as well as for exploring modern control methods (e.g., on-blade controls (OBC)) for alleviating fatigue. This paper discusses comprehensive simulation-based rotorcraft loads/stress analysis and fatigue alleviation control methods toward the goal of minimum maintenance for future vertical lift. The paper covers several aspects, including comprehensive modeling for loads prediction, blade stress analysis with the applied loads, fatigue estimation, and loads/stress reduction control formulation. The paper also presents simulation results that demonstrate the successful reduction of vibratory loads/stress using modern on-blade active control methods.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126399812","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16758
S. Jung, Sung-Boo Hong, J. Bae, Seonguk Hong, Jae-Sang Park
A rotor-body coupled vibration analysis is performed for a coaxial compound lift offset (LO) helicopter. The vehicle is featured by two-bladed counterrotating rotors, main wing, and auxiliary propulsions installed at each wing tip. The fuselage analysis model is constructed considering the existing designs of conventional helicopters and tilt rotors, while the blade structural design is established modifying the original platform of XH-59A blades. As many as 17 free vibrating modes are used to represent the airframe motions after conducting a convergence test on the vibration behavior of the rotor. An in-house structural design optimization framework based on the evolutionary algorithm is employed to systematically search the best suited combinations of the objective function while meeting all the design constraints set from the static and structural dynamics perspectives. The resulting property values of the optimized configuration are correlated with those by XH-59A. The predicted results on the performance show in good agreement with the flight test data of XH-59A. The trim, loads and vibration responses are examined using either isolated coaxial LO or compound coaxial LO rotors. Key results showing the beneficial effects of LO rotor in both configurations are discussed with the shaft-fixed or shaft-free conditions of the compound helicopter in high speed flights.
{"title":"Rotor-Body Coupled Vibration Analysis of a High-Speed Lift Offset Coaxial Rotor","authors":"S. Jung, Sung-Boo Hong, J. Bae, Seonguk Hong, Jae-Sang Park","doi":"10.4050/f-0077-2021-16758","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16758","url":null,"abstract":"\u0000 A rotor-body coupled vibration analysis is performed for a coaxial compound lift offset (LO) helicopter. The vehicle is featured by two-bladed counterrotating rotors, main wing, and auxiliary propulsions installed at each wing tip. The fuselage analysis model is constructed considering the existing designs of conventional helicopters and tilt rotors, while the blade structural design is established modifying the original platform of XH-59A blades. As many as 17 free vibrating modes are used to represent the airframe motions after conducting a convergence test on the vibration behavior of the rotor. An in-house structural design optimization framework based on the evolutionary algorithm is employed to systematically search the best suited combinations of the objective function while meeting all the design constraints set from the static and structural dynamics perspectives. The resulting property values of the optimized configuration are correlated with those by XH-59A. The predicted results on the performance show in good agreement with the flight test data of XH-59A. The trim, loads and vibration responses are examined using either isolated coaxial LO or compound coaxial LO rotors. Key results showing the beneficial effects of LO rotor in both configurations are discussed with the shaft-fixed or shaft-free conditions of the compound helicopter in high speed flights.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125802832","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16820
Maximilian Fischer, Denis Heckmann, A. Nase
Several cities and regions have announced to launch electric Vertical Take-Off and Landing (eVTOL) based air taxi services in the future. To successfully implement such services, the financial viability must be assessed. As part of the project "SkyCab", an eVTOL based air taxi service concept was designed, associated costs to set-up such service assessed, major impact factors on the pricing identified and the willingness-to-pay of the target customers evaluated. The paper outlines the approach to evaluate the financial viability within five steps. First, the target customer group is identified based on the local mobility demand. Second, route network and vertiport locations are selected meeting the target customer trip demand and providing travel time saving benefits. Third, the willingness-to-pay is estimated: Therefore, the average financial power of the target customer groups is determined, and time and comfort advantages of an air taxi service compared to other means of transportation are evaluated. Fourth, the operational costs under consideration of the entire air taxi ecosystem are identified where pilot, aircraft and overhead costs contribute to 2/3 of the overall operational costs. Last, main operational impact factors such as the utilization rate, occupation rate and level of automation driving the financial viability are evaluated.
{"title":"Assessment of the Operational Costs and the Passengers' Willingness-to-Pay to Evaluate the Financial Viability of an Air Taxi Service","authors":"Maximilian Fischer, Denis Heckmann, A. Nase","doi":"10.4050/f-0077-2021-16820","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16820","url":null,"abstract":"\u0000 Several cities and regions have announced to launch electric Vertical Take-Off and Landing (eVTOL) based air taxi services in the future. To successfully implement such services, the financial viability must be assessed. As part of the project \"SkyCab\", an eVTOL based air taxi service concept was designed, associated costs to set-up such service assessed, major impact factors on the pricing identified and the willingness-to-pay of the target customers evaluated. The paper outlines the approach to evaluate the financial viability within five steps. First, the target customer group is identified based on the local mobility demand. Second, route network and vertiport locations are selected meeting the target customer trip demand and providing travel time saving benefits. Third, the willingness-to-pay is estimated: Therefore, the average financial power of the target customer groups is determined, and time and comfort advantages of an air taxi service compared to other means of transportation are evaluated. Fourth, the operational costs under consideration of the entire air taxi ecosystem are identified where pilot, aircraft and overhead costs contribute to 2/3 of the overall operational costs. Last, main operational impact factors such as the utilization rate, occupation rate and level of automation driving the financial viability are evaluated.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"259 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122680262","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16762
Seyhan Gul, A. Datta
A hingeless hub tiltrotor with swept-tip blades was examined comprehensively with a new rotorcraft aeromechanics solver developed at the University of Maryland. The solver was verified with hypothetical U.S. government results and validated with Boeing M222 test data from 1972. A 20◦ sweep back from 80%R increased instability speed to 395 knots, an improvement of 70 knots. The key mechanism is the aerodynamic center shift. The trade-off is the increase in control system loads. Fundamental understanding of the physics is provided. Air resonance emerged as the critical phenomenon, not whirl flutter. Predictions in powered mode is necessary. At least first rotor flap, lag, and torsion modes need to be included. Rotor aerodynamics should use airfoil tables; wing aerodynamics is not important for air resonance. Analysis shows high speed flight is achievable with 13.5% wings but systematic wind tunnel tests with modern equipment is necessary for further validation.
{"title":"Aeroelastic Loads and Stability of Swept-Tip Hingeless Tiltrotors Toward 400 knots Flutter-Free Cruise","authors":"Seyhan Gul, A. Datta","doi":"10.4050/f-0077-2021-16762","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16762","url":null,"abstract":"\u0000 A hingeless hub tiltrotor with swept-tip blades was examined comprehensively with a new rotorcraft aeromechanics solver developed at the University of Maryland. The solver was verified with hypothetical U.S. government results and validated with Boeing M222 test data from 1972. A 20◦ sweep back from 80%R increased instability speed to 395 knots, an improvement of 70 knots. The key mechanism is the aerodynamic center shift. The trade-off is the increase in control system loads. Fundamental understanding of the physics is provided. Air resonance emerged as the critical phenomenon, not whirl flutter. Predictions in powered mode is necessary. At least first rotor flap, lag, and torsion modes need to be included. Rotor aerodynamics should use airfoil tables; wing aerodynamics is not important for air resonance. Analysis shows high speed flight is achievable with 13.5% wings but systematic wind tunnel tests with modern equipment is necessary for further validation.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"307 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123057449","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16688
Chengjian He, J. Baeder, Jeewoong Kim, C. Ware, S. Yang, Y. Jung
Interest in eVTOL air vehicles has increased significantly in recent years. Most development efforts for eVTOL aircraft have addressed conventional performance objectives. However, the acoustic noise remains a critical aspect that must be dealt with due to its significant impact on operations. This paper summarizes a study of eVTOL rotor acoustic noise variation using a CFD augmented comprehensive rotorcraft modeling and simulation tool combined with acoustic analysis that was validated against measured eVTOL drone rotor noise data. The paper presents a thorough parametric investigation of the variation of the rotor/propeller acoustic signature with emphasis on the broadband noise that often dominates in eVTOL rotor/propeller operation. The parametric study has investigated the effect of a range of rotor parameters, including number of rotor blades, rotor solidity, tip Mach number, blade planform (e.g., chord distribution), etc. The study has revealed important acoustic characteristics of eVTOL rotors. Several findings from the study are fundamentally unique to eVTOL rotors, which provide physical insight into supporting low noise eVTOL rotor/propeller design and development.
{"title":"eVTOL Rotor Noise Study Using Combined Comprehensive Modeling with Acoustic Analysis","authors":"Chengjian He, J. Baeder, Jeewoong Kim, C. Ware, S. Yang, Y. Jung","doi":"10.4050/f-0077-2021-16688","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16688","url":null,"abstract":"\u0000 Interest in eVTOL air vehicles has increased significantly in recent years. Most development efforts for eVTOL aircraft have addressed conventional performance objectives. However, the acoustic noise remains a critical aspect that must be dealt with due to its significant impact on operations. This paper summarizes a study of eVTOL rotor acoustic noise variation using a CFD augmented comprehensive rotorcraft modeling and simulation tool combined with acoustic analysis that was validated against measured eVTOL drone rotor noise data. The paper presents a thorough parametric investigation of the variation of the rotor/propeller acoustic signature with emphasis on the broadband noise that often dominates in eVTOL rotor/propeller operation. The parametric study has investigated the effect of a range of rotor parameters, including number of rotor blades, rotor solidity, tip Mach number, blade planform (e.g., chord distribution), etc. The study has revealed important acoustic characteristics of eVTOL rotors. Several findings from the study are fundamentally unique to eVTOL rotors, which provide physical insight into supporting low noise eVTOL rotor/propeller design and development.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130008848","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16822
S. Esteban, Álvaro Blanco
The objective of the presented study is to provide tools for the power plant selection that meet the performance requirements of a VTOL prototype. The tool is integrated in a Mission-Oriented Design Calculator MODC that receives information of the VTOL prototype through a General Block Data (GBD), and then process the information using two algorithms that work together to obtain sub-optimal power plant selections. The data fed to the MODC receives the information of the candidate prototype via four smaller structures that provide geometric, weights, aerodynamic, and propulsive properties that are updated during the iteration process using a series of update rules. This information is then fed to two algorithms: Sensitivity Analysis Algorithm (SAA) and the Fixed-MTOW Analysis Algorithm (FMAA) for the selection of sub-optimal configurations. The SAA generates desired target performance levels for varying aircraft speed (V), propellers' diameter (D), number of engines, and scaling factor SF. The sensitivity analysis provides families of plausible solutions of power plant selections (engine, propeller and batteries) that satisfy the performance target requirements for both axial and longitudinal flight, which are denoted Convergence Zones. The FMAA finds the sub-optimal configuration within the Convergence Zones in order to maximize the Range/Endurance of the UAV for all flight regimes, and extends the study for different combinations for payload and battery mass. After each cycle of iteration the MODC updates the VTOL prototype characteristics in the GBD, hence serving as new data to conduct new sensitivity analysis using the SAA and fine tuning of the FMAA. Results are presented for both algorithms, and conclusions are presented indicating interesting trends towards defining sub-optimal power plant combinations.
{"title":"Parameter Sensitivity studies for the Performance of an Electric BiCP-VTOL UAV","authors":"S. Esteban, Álvaro Blanco","doi":"10.4050/f-0077-2021-16822","DOIUrl":"https://doi.org/10.4050/f-0077-2021-16822","url":null,"abstract":"\u0000 The objective of the presented study is to provide tools for the power plant selection that meet the performance requirements of a VTOL prototype. The tool is integrated in a Mission-Oriented Design Calculator MODC that receives information of the VTOL prototype through a General Block Data (GBD), and then process the information using two algorithms that work together to obtain sub-optimal power plant selections. The data fed to the MODC receives the information of the candidate prototype via four smaller structures that provide geometric, weights, aerodynamic, and propulsive properties that are updated during the iteration process using a series of update rules. This information is then fed to two algorithms: Sensitivity Analysis Algorithm (SAA) and the Fixed-MTOW Analysis Algorithm (FMAA) for the selection of sub-optimal configurations. The SAA generates desired target performance levels for varying aircraft speed (V), propellers' diameter (D), number of engines, and scaling factor SF. The sensitivity analysis provides families of plausible solutions of power plant selections (engine, propeller and batteries) that satisfy the performance target requirements for both axial and longitudinal flight, which are denoted Convergence Zones. The FMAA finds the sub-optimal configuration within the Convergence Zones in order to maximize the Range/Endurance of the UAV for all flight regimes, and extends the study for different combinations for payload and battery mass. After each cycle of iteration the MODC updates the VTOL prototype characteristics in the GBD, hence serving as new data to conduct new sensitivity analysis using the SAA and fine tuning of the FMAA. Results are presented for both algorithms, and conclusions are presented indicating interesting trends towards defining sub-optimal power plant combinations.\u0000","PeriodicalId":273020,"journal":{"name":"Proceedings of the Vertical Flight Society 77th Annual Forum","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124552577","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 : 2021-05-10DOI: 10.4050/f-0077-2021-16807
Ahmad Amer, F. Kopsaftopoulos
With the needs for full structural state awareness and health monitoring as well as emerging challenges of Urban Air Mobility (UAV) and Future Vertical Lift (FVL), Health and Usage Monitoring systems (HUMS) need to be more accurate, robust and reliable than ever before. In active-sensing guided-wave networks in particular, conventional Damage Index (DI)-based approaches have been the industry standard for decades because of their computational simplicity and ability to do the damage detection and quantification tasks. However, under specific circumstances, like for specific actuator-sensor paths within a network or due to varying operational conditions, DIs can suffer from various drawbacks that make them prone to inaccurate and/or ineffective damage quantification. This study builds on previous work by the authors where DIs were used to train single-output Gaussian Process regression models (SOGPRMs) for robust damage quantification, and the accuracy limit of SOGPRMs was shown to depend on the evolution of the chosen DI formulation with damage size. In this study, multi-output GPRMs (MOGPRMs) are used instead in order to leverage information about damage size from multiple actuator-sensor path DI values. It is shown that the proposed approach can overcome the different shortcomings of DI evolution with damage size in the different path by capturing the correlation between the DI evolution for different paths. The proposed framework is applied for an Al coupon with simulated damage, and the damage size quantification results are compared with those of SOGPRMs. It is shown that the information fusion approach exhibited by MOGPRMs gives more accurate damage size estimations compared to SOGPRMs.
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