SAE International Journal of Aerospace最新文献

Computational Investigation of a Flexible Airframe Taxiing Over an Uneven Runway for Aircraft Vibration Testing 飞机振动测试中灵活机身在不平跑道上滑行的计算研究

IF 0.4

SAE International Journal of Aerospace Pub Date : 2023-12-15 DOI: 10.4271/01-17-02-0011

Lohay Al-bess, F. Khouli

{"title":"Computational Investigation of a Flexible Airframe Taxiing Over an\u0000 Uneven Runway for Aircraft Vibration Testing","authors":"Lohay Al-bess, F. Khouli","doi":"10.4271/01-17-02-0011","DOIUrl":"https://doi.org/10.4271/01-17-02-0011","url":null,"abstract":"Ground vibration testing (GVT) is an important phase of the development, or the\u0000 structural modification of an aircraft program. The modes of vibration and their\u0000 associated parameters extracted from the GVT are used to modify the structural\u0000 model of the aircraft to make more reliable dynamics predictions to satisfy\u0000 certification authorities. Due to the high cost and the extensive preparations\u0000 for such tests, a new method of vibration testing called taxi vibration testing\u0000 (TVT) rooted in operational modal analysis (OMA) was recently proposed and\u0000 investigated by the German Institute for Aerospace Research (DLR) as alternative\u0000 to conventional GVT. In this investigation, a computational framework based on\u0000 fully coupled flexible multibody dynamics for TVT is presented to further\u0000 investigate the applicability of the TVT to flexible airframes. The time domain\u0000 decomposition (TDD) method for OMA was used to postprocess the response of the\u0000 airframe during a TVT. The framework was then used to examine the impact of the\u0000 taxiing speed, shock absorber damping coefficient, and bump geometry on the\u0000 outcome of the computational TVT. It was found that higher taxiing speed does\u0000 not necessarily mean a better quality TVT, and one must find the optimal speed\u0000 using the computational framework presented herein. A higher shock absorber\u0000 damping coefficient was found to increase the amplitude of the response during\u0000 the TVT without significantly impacting the extracted modes and their\u0000 frequencies. Also, the quality of the TVT was found to be inversely proportional\u0000 to the curvature of the bump cross section. The proposed TVT computational\u0000 framework is validated against the normal modal analysis technique and certain\u0000 experimental data.","PeriodicalId":44558,"journal":{"name":"SAE International Journal of Aerospace","volume":"45 S5","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139000055","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}

引用次数: 0

Material Recognition Technology of Internal Loose Particles in Sealed Electronic Components Based on Random Forest 基于随机森林的密封电子元件内部松散颗粒材料识别技术

IF 0.4

SAE International Journal of Aerospace Pub Date : 2023-12-05 DOI: 10.4271/01-17-02-0009

Yajie Gao, Guotao Wang, Aiping Jiang, Huizhen Yan

{"title":"Material Recognition Technology of Internal Loose Particles in Sealed\u0000 Electronic Components Based on Random Forest","authors":"Yajie Gao, Guotao Wang, Aiping Jiang, Huizhen Yan","doi":"10.4271/01-17-02-0009","DOIUrl":"https://doi.org/10.4271/01-17-02-0009","url":null,"abstract":"Sealed electronic components are the basic components of aerospace equipment, but\u0000 the issue of internal loose particles greatly increases the risk of aerospace\u0000 equipment. Traditional material recognition technology has a low recognition\u0000 rate and is difficult to be applied in practice. To address this issue, this\u0000 article proposes transforming the problem of acquiring material information into\u0000 the multi-category recognition problem. First, constructing an experimental\u0000 platform for material recognition. Features for material identification are\u0000 selected and extracted from the signals, forming a feature vector, and\u0000 ultimately establishing material datasets. Then, the problem of material data\u0000 imbalance is addressed through a newly designed direct artificial sample\u0000 generation method. Finally, various identification algorithms are compared, and\u0000 the optimal material identification model is integrated into the system for\u0000 practical testing. The results show that the proposed material identification\u0000 technology achieves an accuracy rate of 85.7% in distinguishing between metal\u0000 and nonmetal materials, and an accuracy rate of 73.8% in identifying specific\u0000 materials. This result surpasses the accuracy rates achieved by all currently\u0000 known identification techniques. At the same time, this technology represents\u0000 the latest expansion in the field of loose particles detection and holds\u0000 significant practical value for improving system robustness. The proposed\u0000 technique theoretically can be widely applied to other fault diagnosis fields\u0000 with similar signal generation mechanisms.","PeriodicalId":44558,"journal":{"name":"SAE International Journal of Aerospace","volume":"125 35","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138599220","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}

引用次数: 0

External Synchronization of Distributed Redundant Flight Control Computers 分布式冗余飞行控制计算机的外部同步

IF 0.4

SAE International Journal of Aerospace Pub Date : 2023-12-01 DOI: 10.4271/01-17-02-0010

Mokhamad Khozin, Florian Holzapfel

{"title":"External Synchronization of Distributed Redundant Flight Control\u0000 Computers","authors":"Mokhamad Khozin, Florian Holzapfel","doi":"10.4271/01-17-02-0010","DOIUrl":"https://doi.org/10.4271/01-17-02-0010","url":null,"abstract":"This work introduces a practical approach to external synchronization for flight\u0000 control computers (FCCs) deployed in a decentralized fashion. The internal\u0000 synchronization among the FCCs in distributed flight control systems needs to be\u0000 extended for specific applications, necessitating an urgent need for an external\u0000 synchronization mechanism. For instance, when the air data and attitude\u0000 reference system (ADAHRS) and the flight control computer (FCC) are not\u0000 synchronized, a dead time or time offset occurs between the time the ADAHRS\u0000 transmits data and the time the FCC begins executing its control functions,\u0000 which can impair flight control system performance or even cause system\u0000 instability, particularly for the system with incremental control approaches,\u0000 such as incremental nonlinear dynamic inversion (INDI). Therefore, an external\u0000 synchronization technique that does not rely on establishing a global view of\u0000 time that is accurately synchronized with an external reference device has been\u0000 proposed and implemented for distributed flight control systems. The findings of\u0000 the implemented system demonstrate that the suggested approach can synchronize\u0000 the distributed FCCs to an external reference device with high synchronization\u0000 precision and deal with varying clock drift rates.","PeriodicalId":44558,"journal":{"name":"SAE International Journal of Aerospace","volume":" 18","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138617447","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}

引用次数: 0

Reviewers 评论家

SAE International Journal of Aerospace Pub Date : 2023-10-18 DOI: 10.4271/01-16-03-0024

Ravi Rajamani

引用次数: 0

Determination of the Heat-Controlled Accumulator Volume for the Two-Phase Thermal Control Systems of Spacecraft 航天器两相热控系统热控蓄热器体积的确定

SAE International Journal of Aerospace Pub Date : 2023-09-29 DOI: 10.4271/01-17-01-0008

Artem Hodunov, Gennadiy Gorbenko, Rustem Turna, Polina Koval

{"title":"Determination of the Heat-Controlled Accumulator Volume for the Two-Phase Thermal Control Systems of Spacecraft","authors":"Artem Hodunov, Gennadiy Gorbenko, Rustem Turna, Polina Koval","doi":"10.4271/01-17-01-0008","DOIUrl":"https://doi.org/10.4271/01-17-01-0008","url":null,"abstract":"<div>For spacecraft with high power consumption, it is reasonable to build the thermal control system based on a two-phase mechanically pumped loop. The heat-controlled accumulator is a key element of the two-phase mechanically pumped loop, which allows for the control of pressure in the loop and maintains the required level of coolant boiling temperature or cavitation margin at the pump inlet. There can be two critical modes of loop operation where the ability to control pressure will be lost. The first critical mode occurs when the accumulator fills with liquid at high heat loads. The second critical mode occurs when the accumulator is at low heat loads and partial loss of coolant, for example, due to the leak caused by micrometeorite breakdown. Both modes are caused by insufficient accumulator volume or working fluid charge. To analyze the loop characteristics in critical modes, experiments were conducted on a test bench with ammonia coolant, and a mathematical simulation of a two-phase mechanically pumped loop was performed. The results show that the loop can operate in critical modes in a certain range of heat loads. The conducted studies allow for the design of a heat-controlled accumulator with the minimum required volume, expand the performance range of a two-phase mechanically pumped loop, and increase the reliability of its operation in orbit during long-term missions.</div>","PeriodicalId":44558,"journal":{"name":"SAE International Journal of Aerospace","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135294780","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}

引用次数: 0

Letter from the Special Issue Editors 特刊编辑的来信

SAE International Journal of Aerospace Pub Date : 2023-09-18 DOI: 10.4271/01-16-03-0017

Andy Wallington

引用次数: 0

Nonlinear Observer for Estimating Gravity Vector and Flight Path Angles of a High-Performance Aircraft 估计高性能飞机重力矢量和飞行轨迹角的非线性观测器

IF 0.4

SAE International Journal of Aerospace Pub Date : 2023-08-14 DOI: 10.4271/01-17-01-0007

K. Chandrasekaran, Shikha Jain

引用次数: 0

Experimental and Numerical Investigation of Combustion and Noise, Vibrations, and Harshness Emissions in a Drone Jet Engine Fueled with Synthetic Paraffinic Kerosene 以合成石蜡煤油为燃料的无人机喷气发动机燃烧、噪声、振动和粗糙度排放的实验和数值研究

SAE International Journal of Aerospace Pub Date : 2023-08-14 DOI: 10.4271/01-17-01-0006

Valentin Soloiu, John Mcafee, Marcel Ilie, Aidan Rowell, James Willis, Nicholas Dillon

{"title":"Experimental and Numerical Investigation of Combustion and Noise, Vibrations, and Harshness Emissions in a Drone Jet Engine Fueled with Synthetic Paraffinic Kerosene","authors":"Valentin Soloiu, John Mcafee, Marcel Ilie, Aidan Rowell, James Willis, Nicholas Dillon","doi":"10.4271/01-17-01-0006","DOIUrl":"https://doi.org/10.4271/01-17-01-0006","url":null,"abstract":"<div>Emissions and effects of climate change have prompted study into fuels that reduce global dependence on traditional fuels. This study seeks to investigate engine performance, thermochemical properties, emissions, and perform NVH analysis of Jet-A and S8 using a single-stage turbojet engine at three engine speeds. Experimental Jet-A results were used to validate a CFX simulation of the engine. Engine performance was quantified using thermocouples, pressure sensors, tachometers, flow meters, and load cells fitted to the engine. Emissions results were collected using an MKS Multigas Emissions Analyzer that examined CO, CO₂, H₂O, NOx, and THC. NVH analysis was conducted using a multifield, free-field microphone, and triaxial accelerometer. This study found that Jet-A operates at higher temperatures and pressures than S8, and S8 requires higher fuel flow rates than Jet-A, leading to poorer efficiency and thrust. S8 produced stronger vibrations over 5 kHz compared to Jet-A. S8 showed a decrease in all measured emissions. The CFD model was validated, showing an increase in temperature, pressure, and gas velocity as speed increased. The swirl effect of combustion was examined, improving atomization. Emissions contours were validated by experimental results, showing increases in CO₂, H₂O, and NOx, and a decrease in CO as speed increases.</div>","PeriodicalId":44558,"journal":{"name":"SAE International Journal of Aerospace","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135265475","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}

引用次数: 0

Criticality of Prognostics in the Operations of Autonomous Aircraft 预测在自主飞机操作中的重要性

IF 0.4

SAE International Journal of Aerospace Pub Date : 2023-06-28 DOI: 10.4271/01-16-03-0022

G. Vachtsevanos, R. Rajamani

{"title":"Criticality of Prognostics in the Operations of Autonomous\u0000 Aircraft","authors":"G. Vachtsevanos, R. Rajamani","doi":"10.4271/01-16-03-0022","DOIUrl":"https://doi.org/10.4271/01-16-03-0022","url":null,"abstract":"This article addresses the design, testing, and evaluation of rigorous and\u0000 verifiable prognostic and health management (PHM) functions applied to\u0000 autonomous aircraft systems. These PHM functions—many deployed as algorithms—are\u0000 integrated into a holistic framework for integrity management of aircraft\u0000 components and systems that are subject to both operational degradation and\u0000 incipient failure modes. The designer of a comprehensive and verifiable\u0000 prognostics system is faced with significant challenges. Data (both baseline and\u0000 faulted) that are correlated, time stamped, and appropriately sampled are not\u0000 always readily available. Quantifying uncertainty, and its propagation and\u0000 management, which are inherent in prognosis, can be difficult. High-fidelity\u0000 modeling of critical components/systems can consume precious resources. Data\u0000 mining tools for feature extraction and selection are not easy to develop and\u0000 maintain. And finally, diagnostic and prognostic algorithms that address\u0000 accurately the designer’s specifications are not easy to develop, verify,\u0000 deploy, and sustain. These are just the technical challenges. On top of these\u0000 are business challenges, for example, demonstrating that the PHM functionality\u0000 will be economically beneficial to the system stakeholders, and finally, there\u0000 are regulatory challenges, such as, assuring the authorities that the PHM system\u0000 will have the necessary safety assurance levels while delivering its performance\u0000 goals. This article tackles all three aspects of the use of PHM systems in\u0000 autonomous systems. It outlines how some of the technical challenges have been\u0000 overcome and demonstrates why PHM could be essential in this ecosystem and why\u0000 regulatory authorities are increasingly open to the use of PHM systems even in\u0000 the most safety-critical areas of aviation.","PeriodicalId":44558,"journal":{"name":"SAE International Journal of Aerospace","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45779580","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}

引用次数: 0

Three Case Studies on Small Uncrewed Aerial Systems Near Midair Collisions with Aircraft: An Evidence-Based Approach for Using Objective Uncrewed Aerial Systems Detection Technology 小型无人机系统与飞机空中碰撞的三个案例研究:基于证据的无人机系统目标检测技术应用方法

IF 0.4

SAE International Journal of Aerospace Pub Date : 2023-06-14 DOI: 10.4271/01-16-03-0023

Ryan Wallace, S. Winter, S. Rice, David C. Kovar, Sang-A Lee

{"title":"Three Case Studies on Small Uncrewed Aerial Systems Near Midair\u0000 Collisions with Aircraft: An Evidence-Based Approach for Using Objective\u0000 Uncrewed Aerial Systems Detection Technology","authors":"Ryan Wallace, S. Winter, S. Rice, David C. Kovar, Sang-A Lee","doi":"10.4271/01-16-03-0023","DOIUrl":"https://doi.org/10.4271/01-16-03-0023","url":null,"abstract":"Small uncrewed aircraft systems (sUAS) growth continues for recreational and\u0000 commercial applications. By 2025, the Federal Aviation Administration (FAA)\u0000 predicts the sUAS fleet to number nearly 2.4 million units. As sUAS operations\u0000 expand within the National Airspace System (NAS), so too does the probability of\u0000 near midair collisions (NMACs) between sUAS and aircraft. Currently, the primary\u0000 means of recognizing sUAS NMACs rely on pilots to visually spot and evade\u0000 conflicting sUAS. Pilots may report such encounters to the FAA as UAS Sighting\u0000 Reports. Sighting reports are of limited value as they are highly subjective and\u0000 dependent on the pilot to accurately estimate range and altitude information.\u0000 Moreover, they do not account for NMACs that an aircrew member does not spot.\u0000 The purpose of this study was to examine objective sUAS and aircraft telemetry\u0000 data collected using a DJI Aeroscope sensor and Automatic Dependent\u0000 Surveillance-Broadcast (ADS-B)/Mode S messages throughout 36 months near a major\u0000 United States (U.S.) airport. This data offers objective insights into the\u0000 interaction of sUAS and aircraft in the airspace surrounding this airport. Using\u0000 the data, three NMAC case studies are presented based on three varying mission\u0000 profiles: (a) commercial air carriers, (b) general aviation (GA) aircraft, and\u0000 (c) helicopters. The findings inform on sUAS-aircraft encounter evolution and\u0000 trends, including areas of encounter risk, lateral and vertical encounter\u0000 separation distances, sUAS operator compliance with operational and altitude\u0000 restrictions, and comparisons of objective detection data against sUAS sighting\u0000 reports. Recommendations are provided to mitigate risks associated with\u0000 encounter trends to further enhance safety within the NAS.","PeriodicalId":44558,"journal":{"name":"SAE International Journal of Aerospace","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47074940","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}

引用次数: 1