Global ETD Search

181	Conceptual Design of a South Pole Carrier Pigeon UAV Dlima, Kendrick M 01 June 2020 (has links) Currently, the South Pole has a large data problem. It is estimated that 1.2 TB of data is being produced every day, but less than 500 GB of that data is being uploaded via aging satellites to researchers in other parts of the world. This requires those at the South Pole to analyze the data and carefully select the parts to send, possibly missing out on vital scientific information. The South Pole Carrier Pigeon will look to bridge this data gap. The Carrier Pigeon will be a small unmanned aerial vehicle that will carry a 30 TB solid-state hard drive from the South Pole to various destinations in the Southern Hemisphere, but it has been designed to y to Christchurch, New Zealand. This 87 lb. UAV will be able to y 3,650 nmi. up to 25,000 ft., using a 5.7 hp. engine. It will feature an de-icing system on the leading edge of its 8 ft. span wing to allow it to y through cold, moist climates. It will have a 39 in. long fuselage with a tail boom of 33 in. The aircraft has been designed to be made out of composites, thus reducing both the weight of the aircraft as well as its drag. It has been designed to come apart in order to be shipped successfully to the South Pole. There, it will be assembled and launched via a custom pneumatic launcher. It will y autonomously to 15,000 ft. and cruise climb throughout the flight to 25,000 ft., before descending to its destination. There, it will be caught by a net restraint system, where the hard drive will be extracted. The Carrier Pigeon is truly a unique vehicle for its size, range, and robustness. UAV Carrier Pigeon South Pole Antarctica Conceptual Design Data Transfer Aerodynamics and Fluid Mechanics Aeronautical Vehicles Aerospace Engineering Aviation and Space Education Climate Management and Operations Meteorology Propulsion and Power
182	Developing systems engineering and machine learning frameworks for the improvement of aviation maintenance Elakramine, Fatine 12 May 2023 (has links) (PDF) This dissertation develops systems engineering and machine learning models for aviation maintenance support. With the constant increase in demand for air travel, aviation organizations compete to maintain airworthy aircraft to ensure the safety of passengers. Given the importance of aircraft safety, the aviation sector constantly needs technologies to enhance the maintenance experience, ensure system safety, and limit aircraft downtime. Based on the current literature, the aviation maintenance sector still relies on outdated technologies to maintain aircraft maintenance documentation, including paper-based technical orders. Aviation maintenance documentation contains a mixture of structured and unstructured technical text, mainly inputted by operators, making them prone to error, misunderstanding communication, and inconsistency. This dissertation intends to develop decision support models based on systems engineering and artificial intelligence models that can automate the maintenance documentation system, extract useful information from maintenance work orders, and predict the aircraft's top degrader signals based on textual data. The first chapter of this dissertation introduces the significant setbacks of the aviation industry and provides a working ground for the following chapters. The dissertation's second chapter develops a system engineering framework using model-based systems engineering (MBSE) methodology to model the aviation maintenance process using the systems engineering language (SysML). The outcome of this framework is the design of an automated maintenance system model that can be used to automate maintenance documentation, making it less prone to error. The third chapter of the dissertation uses textual data in maintenance work orders to develop a hybrid approach that uses natural language processing (NLP) and transformer models to predict the readiness of a legacy aircraft. The model was tested using a real-life case study of the EA-6B military aircraft. The fourth chapter of this dissertation develops an ensemble transformer model based on three different transformer models. The ensemble model leverages the benefits of three different transformer architectures and is used to classify events based on an aviation log-based dataset. This dissertation's final and fifth chapter summarizes key findings, proposes future work directions, and provides the dissertation's limitations. aviation maintenance data-driven approaches transformer model model-based systems engineering systems modeling language Aviation Safety and Security Industrial Engineering Industrial Technology Maintenance Technology Systems Engineering
183	Design, Fabrication, and Testing of an EMR Based Orbital Debris Impact Testing Platform Maniglia, Jeffrey J, Jr. 01 June 2013 (has links) (PDF) This paper describes the changes made from Cal Poly’s initial railgun system, the Mk. 1 railgun, to the Mk. 1.1 system, as well as the design, fabrication, and testing of a newer and larger Mk. 2 railgun system. The Mk. 1.1 system is developed as a more efficient alteration of the original Mk. 1 system, but is found to be defective due to hardware deficiencies and failure, as well as unforeseen efficiency losses. A Mk. 2 system is developed and built around donated hardware from the Naval Postgraduate School. The Mk. 2 system strove to implement an efficient, augmented, electromagnetic railgun and projectile system capable of firing an approximate 1g aluminum projectile to speeds exceeding 2 km/s. A novel three part projectile is proposed to mitigate rail and projectile degradation. Projectile and sabot system kinematic equations are derived and the projectile is designed and tested along with Mk. 2 barrel. A numerical electromechanical model is developed to predict the performance of the Mk. 2 system and projectile assembly, and predicts a final velocity for the fabricated system exceeding 3.5 km/s and an efficiency as high as 24%. Testing of the Mk. 2 system showed catastrophic failure of the projectile during initial acceleration, resulting in very short acceleration times and distance, low velocity projectiles, and low efficiencies. During further testing of various projectile configurations, the barrel structure failed due to a large internal arc. Future work for the Mk. 2 system is discussed, a revised external barrel structure suggested, and a solid, more conventional solid chevron projectile design suggested. electromagnetic rail gun orbital debris hypersonic Applied Mechanics Astrodynamics Electrical and Electronics Electromagnetics and Photonics Electro-Mechanical Systems Other Aerospace Engineering Power and Energy Space Vehicles Structures and Materials
184	Performance Enhancement and Characterization of an Electromagnetic Railgun Gilles, Paul M 01 December 2019 (has links) (PDF) Collision with orbital debris poses a serious threat to spacecraft and astronauts. Hypervelocity impacts resulting from collisions mean that objects with a mass less than 1g can cause mission-ending damage to spacecraft. A means of shielding spacecraft against collisions is necessary. A means of testing candidate shielding methods for their efficacy in mitigating hypervelocity impacts is therefore also necessary. Cal Poly’s Electromagnetic Railgun was designed with the goal of creating a laboratory system capable of simulating hypervelocity (≥ 3 km/s) impacts. Due to several factors, the system was not previously capable of high-velocity (≥ 1 km/s) tests. A deficient projectile design is revised, and a new design is tested. The new projectile design is demonstrated to enable far greater performance than the previous design, with a muzzle velocity ≥ 1 km/sbeing verified during testing, and an energy conversion efficiency of 2.7%. A method of improving contact and controlling wear at the projectile/rail interface using silver plating and conductive silver paste is validated. A mechanism explaining the problem of internal arcing within the railgun barrel is proposed, and design recommendations are made to eliminate arcing on the basis of the work done during testing. The primary structural members are found to be deficient for their application and a failure analysis of a failed member, loading analysis of the railgun barrel, and design of new structures is undertaken and presented. Railgun Hypervelocity Capacitor High Voltage Aerospace Engineering Astrodynamics Electrical and Electronics Electromagnetics and Photonics Other Aerospace Engineering Power and Energy Propulsion and Power Space Habitation and Life Support Space Vehicles Structures and Materials
185	A Comparison Of Western And Eastern Soft Systems Approaches Anaya, John L, Anaya, John L, Anaya, John L 01 March 2024 (has links) (PDF) Soft System Approaches have been developed worldwide to help problem-solvers and decision-makers develop solutions to complex problems, such as aerospace systems. Soft System Approaches were designed to help lower the disorder of developing a complex system by increasing understanding of a situation. Four Soft System Approaches were investigated, two from the West and two from the East. Within the context of the paper, the West refers to thought patterns associated with thinkers and scientists in Europe and North America, and the East refers to those from and around China. The two from the West are Peter Checkland’s Soft Systems Methodology and Fran Ackerman and Colin Eden’s Strategic Options Development and Analysis, and from the East they are Qian Xuesen’s Meta-Synthetic Approach and Jifa Gu and Zhichang Zhu’s Wuli-Shili-Renli Approach. The four approaches were selected due to their prevalence and notoriety within the Soft System Approach research. The Western Soft System Approaches were created as a direct response to reductionism and are more holistic than Hard System Approaches; however, they are classified as systematic due to their structure. The approaches are tools that can be deployed for a specific task. Eastern Soft System Approaches rooted in Eastern philosophy went from holism to reductionism to a unity of the two. There is no one-size-fits-all approach; therefore, approaches that seek to balance reductionism and holism and give guidance and structure while inviting in other methods. The Eastern approaches are classified as framework Soft System Approaches, which provide structure and guidance but not a formula. Systematic approaches are better for determining a course of action, while framework approaches are better for guiding a whole program. The Eastern approaches covered can and do incorporate other methods, including each other. Depending on the problem and problem solver, the systematic or framework approach may be better suited. Overall, however, the framework approach will be able to solve the most varied problems due to the lack of prescriptiveness and the use of other approaches. Knowing the difference between the approaches and how they can be used helps manage the development of complex aerospace systems. Holism Soft System Approach Soft Systems Methodology Meta-Synthetic Approach Wuli-Shili-Renli Engineering Education Other Aerospace Engineering Other Engineering Outdoor Education
186	Landing-Gear Impact Response: A Non-linear Finite Element Approach Tran, Tuan H 01 January 2019 (has links) The primary objective of this research is to formulate a methodology of assessing the maximum impact loading condition that will incur onto an aircraft’s landing gear system via Finite Element Analysis (FEA) and appropriately determining its corresponding structural and impact responses to minimize potential design failures during hard landing (abnormal impact) and shock absorption testing. Both static and dynamic loading condition were closely analyzed, compared, and derived through the Federal Aviation Administration’s (FAA) airworthiness regulations and empirical testing data. In this research, a nonlinear transient dynamic analysis is developed and established via NASTRAN advanced nonlinear finite element model (FEM) to simulate the worst-case loading condition. Under the appropriate loading analysis, the eye-bar and contact patch region theory were then utilized to simulate the tire and nose wheel interface more accurately. The open geometry of the nose landing gear was also optimized to minimize the effect of stress concentration. The result of this research is conformed to the FAA’s regulations and bound to have an impact on the design and development of small and large aircraft’s landing gear for both near and distant future. Thesis University of North Florida UNF aircraft landing gear Applied Mechanics Aviation Safety and Security Computer-Aided Engineering and Design Dynamics and Dynamical Systems Engineering Mechanics Operational Research Risk Analysis Structures and Materials
187	Numerical Modeling and Characterization of Vertically Aligned Carbon Nanotube Arrays Joseph, Johnson 01 January 2013 (has links) Since their discoveries, carbon nanotubes have been widely studied, but mostly in the forms of 1D individual carbon nanotube (CNT). From practical application point of view, it is highly desirable to produce carbon nanotubes in large scales. This has resulted in a new class of carbon nanotube material, called the vertically aligned carbon nanotube arrays (VA-CNTs). To date, our ability to design and model this complex material is still limited. The classical molecular mechanics methods used to model individual CNTs are not applicable to the modeling of VA-CNT structures due to the significant computational efforts required. This research is to develop efficient structural mechanics approaches to design, model and characterize the mechanical responses of the VA-CNTs. The structural beam and shell mechanics are generally applicable to the well aligned VA-CNTs prepared by template synthesis while the structural solid elements are more applicable to much complex, super-long VA-CNTs from template-free synthesis. VA-CNTs are also highly “tunable” from the structure standpoint. The architectures and geometric parameters of the VA-CNTs have been thoroughly examined, including tube configuration, tube diameter, tube height, nanotube array density, tube distribution pattern, among many other factors. Overall, the structural mechanics approaches are simple and robust methods for design and characterization of these novel carbon nanomaterials CNT Carbon nanotube SWCNT Single walled carbon nanotube DWCNT Double walled carbon nanotube MWCNT Multi walled carbon nanotube VA-CNT Vertically aligned carbon nanotube CVD Chemical vapor deposition EAD / CAD Applied Mechanics Nanoscience and Nanotechnology Other Mechanical Engineering Structural Materials Structures and Materials
188	Low Cost Fpga Based Digital Beamforming Architecture for Casa Weather Radar Applications Seguin, Emmanuel J 01 January 2010 (has links) (PDF) Digital beamforming is a powerful signal processing technique used in many communication and radar sensing applications. However, despite its many advantages, its high cost makes it a less popular choice than other directional antenna options. The development of a low cost architecture for digital beamforming would make it a more feasible option, allowing it to be used for a number of new applications. Specifically, the Collaborative, Adaptive Sensing of the Atmosphere (CASA) project’s Distributed Collaborative Adaptive Sensing (DCAS) system, a low cost weather radar system, could benefit from the incorporation of digital beamforming into small, inexpensive but highly functional radars. Existing DBF architectures are implemented in complex systems which include a number of expensive processing modules and other associated hardware. This project shows a low-cost digital beamforming architecture that has been developed by utilizing today’s powerful and inexpensive FPGA devices along with recently available low-voltage-differential-signaling enabled multi-channel analog to digital conversion hardware. The utilization of commercially available devices rather than custom hardware allows this architecture to be manufactured at a fraction of the cost of most. This makes it a viable alternative to the classic dish antennas for the DCAS system, allowing a reduction in size and cost which will benefit deployment. The flexibility of an FPGA-based DBF system will result in a more robust radar system. With this in mind, an architecture has been developed, fabricated and evaluated. Phase Tilt Digital Beamforming FPGA Low Cost Radar CASA Atmospheric Sciences Computer and Systems Architecture Digital Circuits Digital Communications and Networking Electrical and Electronics Environmental Monitoring Hardware Systems Numerical Analysis and Computation Signal Processing Systems and Communications
189	Probabilistic Multidisciplinary Design Optimization on a high-pressure sandwich wall in a rocket engine application Wahlström, Dennis January 2017 (has links) A need to find better achievement has always been required in the space industrythrough time. Advanced technologies are provided to accomplish goals for humanityfor space explorer and space missions, to apprehend answers and widen knowledges. These are the goals of improvement, and in this thesis, is to strive and demandto understand and improve the mass of a space nozzle, utilized in an upperstage of space mission, with an expander cycle engine. The study is carried out by creating design of experiment using Latin HypercubeSampling (LHS) with a consideration to number of design and simulation expense.A surrogate model based optimization with Multidisciplinary Design Optimization(MDO) method for two different approaches, Analytical Target Cascading (ATC) and Multidisciplinary Feasible (MDF) are used for comparison and emend the conclusion. In the optimization, three different limitations are being investigated, designspace limit, industrial limit and industrial limit with tolerance. Optimized results have shown an incompatibility between two optimization approaches, ATC and MDF which are expected to be similar, but for the two limitations, design space limit and industrial limit appear to be less agreeable. The ATC formalist in this case dictates by the main objective, where the children/subproblems only focus to find a solution that satisfies the main objective and its constraint. For the MDF, the main objective function is described as a single function and solved subject to all the constraints. Furthermore, the problem is not divided into subproblems as in the ATC. Surrogate model based optimization, its solution influences by the accuracy ofthe model, and this is being investigated with another DoE. A DoE of the full factorial analysis is created and selected to study in a region near the optimal solution.In such region, the result has evidently shown to be quite accurate for almost allthe surrogate models, except for max temperature, damage and strain at the hottestregion, with the largest common impact on inner wall thickness of the space nozzle. Results of the new structure of the space nozzle have shown an improvement of mass by ≈ 50%, ≈ 15% and ≈ -4%, for the three different limitations, design spacelimit, industrial limit and industrial limit with tolerance, relative to a reference value,and ≈ 10%, ≈ 35% and ≈ 25% cheaper to manufacture accordingly to the defined producibility model. Multidisciplinary Design Optimization Analytical Target Cascading Multidisciplinary Feasible Space Nozzle Ariane Expander Cycle Engine Upper stage space rocket engine Probabilistic Augmented Lagrangian relaxation Finite element Solid Mechanics Thermodynamics Aerodynamics Industrial approach Latin Hypercube Sampling Factorial Analysis Analysis of Variance Other Physics Topics Annan fysik Aerospace Engineering Rymd- och flygteknik Probability Theory and Statistics Sannolikhetsteori och statistik Vehicle Engineering Farkostteknik Reliability and Maintenance Tillförlitlighets- och kvalitetsteknik Applied Mechanics Teknisk mekanik Computational Mathematics Beräkningsmatematik Fluid Mechanics and Acoustics Strömningsmekanik och akustik

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