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Articles 481 - 510 of 518
Full-Text Articles in Aerospace Engineering
Spacecraft Fire Safety Research: Combustion Of Lithium-Ion Batteries To Predict Fire Scenarios, Elisabeth Meyer
Spacecraft Fire Safety Research: Combustion Of Lithium-Ion Batteries To Predict Fire Scenarios, Elisabeth Meyer
Williams Honors College, Honors Research Projects
The purpose of this project was to research characteristics of a Lithium-ion battery fire to determine if trends exist in measured fire characteristics that can help predict different fire scenarios. These experiments will ultimately aid in developing an alarm threshold for a spacecraft smoke detector, specifically for Orion, a new, multi-purpose crew vehicle under development by NASA. Orion is the next-generation of spacecraft designed to replace the space shuttle and will play an important role in NASA’s journey to Mars.
In the experiments performed, Lithium-ion batteries were placed in a test chamber and ignited while smoke concentration was measured, simulating …
Take-Off Characteristics For Naca 4612 Aerofoil In A Twin-Wing Configuration With Optimum Angles Of Attack, Elena Vishnevskaya, Kenneth L. Witcher, Ian R. Mcandrew
Take-Off Characteristics For Naca 4612 Aerofoil In A Twin-Wing Configuration With Optimum Angles Of Attack, Elena Vishnevskaya, Kenneth L. Witcher, Ian R. Mcandrew
Publications
Unmanned Aerial Vehicles are used generally at low levels and speeds. The research reported in this article investigates the possible use of twin-wing designs for higher altitudes with a focus on the possible lift capable for either short runways or high payloads. The wing aerofoil and unique Angles of Attack, AoA, are set 5o on the upper wing and 10o on the lower. There is a positive upper wing stagger of 50% of the chord length at height separation of 1 chord. These parameters have been established from previous research and this research investigates how they generate lift at take-off …
How Nationality, Weather, Wind, And Distance Affect Consumer Willingness To Fly In Autonomous Airplanes, Nadine K. Ragbir, Bradley S. Baugh, Stephen Rice, Scott R. Winter
How Nationality, Weather, Wind, And Distance Affect Consumer Willingness To Fly In Autonomous Airplanes, Nadine K. Ragbir, Bradley S. Baugh, Stephen Rice, Scott R. Winter
Publications
Several studies have examined passengers’ trust in human-operated systems versus autonomous systems. Prior studies have also reported cultural differences among individuals from India and the United States. The purpose of this study was to investigate how nationality, weather, wind, and distance affect passengers’ willingness to fly in autonomous aircraft. Participants included 161 volunteers from the United States and 137 volunteers from India. In 12 different conditions, participants were asked to rate their willingness to fly in an autonomous aircraft, given information about the weather (sunny, raining, or snowing), the wind level (no wind versus strong wind), and the flight distance …
Multitarget Tracking And Terrain-Aided Navigation Using Square-Root Consider Filters, James Samuel Mccabe
Multitarget Tracking And Terrain-Aided Navigation Using Square-Root Consider Filters, James Samuel Mccabe
Doctoral Dissertations
"Filtering is a term used to describe methods that estimate the values of partially observed states, such as the position, velocity, and attitude of a vehicle, using current observations that are corrupted due to various sources, such as measurement noise, transmission dropouts, and spurious information. The study of filtering has been an active focus of research for decades, and the resulting filters have been the cornerstone of many of humankind's greatest technological achievements. However, these achievements are enabled principally by the use of specialized techniques that seek to, in some way, combat the negative impacts that processor roundoff and truncation …
Investigation Of The Onset Of Cavitation In Additively Manufactured Venturis, Erik Korzon
Investigation Of The Onset Of Cavitation In Additively Manufactured Venturis, Erik Korzon
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Optical Analysis Of High Pressure Microplasma Discharges, Noah Latham
Optical Analysis Of High Pressure Microplasma Discharges, Noah Latham
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Design Of Shape-Conforming Nosecone For Optimal Fluid Flow From Transonic To Supersonic Range, Anna Tombazzi
Design Of Shape-Conforming Nosecone For Optimal Fluid Flow From Transonic To Supersonic Range, Anna Tombazzi
Williams Honors College, Honors Research Projects
Modern flight vehicles, such as rockets, missiles, and airplanes, experience a force caused by forebody wave drag during the flight. This drag force is induced when the frontal point of each vehicle breaks the pressure wave during flight. Efforts to reduce this wave drag force to improve flight efficiency include modifying the nosecone profile of the flight vehicles to lower the drag force.
This project revolved around creating a design to make the transformation of nosecone shapes from a ¾ Parabolic profile to a ½ Power Series profile possible, mid-flight. Using a novel nosecone assembly, shape memory alloys (SMAs) and …
Development Of A Supplier’S Delivery Time And Delivered Quality Performance Index And Assessment Of Alternative Decisions Regarding Underperforming Suppliers For The Aerospace Industry, Clint Saidy
Theses and Dissertations
This study investigates current practices of supplier’s delivery assessment so that a comprehensive index and a cost function model could be properly developed. Following a thorough literature review, a framework was created based on a penalty cost function that integrates both suppliers’ ability to deliver on time, as well as suppliers’ capability to deliver good quality. Afterward, suppliers could then be ranked and placed either in good standing, or transversely on probation. Underperforming suppliers face three potential outcomes based on current literature: (1) switching supplier, (2) increase collaboration, (3) maintaining the status quo. The decision vis-à-vis failing suppliers is based …
Erosion Degradation Characteristics Of A Linear Electro-Hydrostatic Actuator Under A High-Frequency Turbulent Flow Field, Yuan Li, Shaoping Wang, Mileta M. Tomovic, Chao Zhang
Erosion Degradation Characteristics Of A Linear Electro-Hydrostatic Actuator Under A High-Frequency Turbulent Flow Field, Yuan Li, Shaoping Wang, Mileta M. Tomovic, Chao Zhang
Engineering Technology Faculty Publications
The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator (LEHA). Rather than the traditional statistical methods based on degradation data, the method proposed in this paper firstly analyzes the dominant progressive failure mode of the LEHA based on the working principle and working conditions of the LEHA. The Computational Fluid Dynamics (CFD) method, combining the turbulent theory and the micro erosion principle, is used to establish an erosion model of the rectification mechanism. The erosion rates for different port openings, under a time-varying flow field, are obtained. The piecewise linearization …
Efficient Design Optimization Methodology For Nonconventional Laminated Thin-Walled Composite Structures, Mazen Albazzan
Efficient Design Optimization Methodology For Nonconventional Laminated Thin-Walled Composite Structures, Mazen Albazzan
Theses and Dissertations
Structural designers seek the best possible design of a structure that optimally meets the requirements of a specific application. The measure of the quality of the final design can often be related to specific stiffness and strength of the structure. Because of their superior mechanical and environmental properties compared to traditional metals, fiberreinforced composite materials have earned a widespread acceptance for different structural applications. The tailoring potential of composites to achieve high specific stiffness and strength has promoted them as promising candidates for constructing lightweight structures. From that aspect, designers have tackled the problem of designing composite laminates, which is …
Evaluating The Effect Of Turbulence On Aircraft During Landing And Take-Off Phases, Anthony O' Connor, Derek Kearney
Evaluating The Effect Of Turbulence On Aircraft During Landing And Take-Off Phases, Anthony O' Connor, Derek Kearney
International Journal of Aviation, Aeronautics, and Aerospace
—— Low level wind shear and turbulence present a serious safety risk to aircraft during the approach, landing and take-off phases. Low level wind shear has been identified as one of the primary factors for aircraft go-arounds and aborted landings. During any given year, wind shear occurs thousands of times at airports around the world, affecting the arrival and departure of aircraft. This paper has quantified the direct cost of flight Go-arounds. This paper will show the potential savings to the aviation industry. This paper will argue that a solution to the problem of forecasting low level wind shear and …
Design Of Revising Proximity Between Space And Time Cues On Flight Deck Displays To Support Nextgen – The First Phase, Chang-Geun Oh, Jennie J. Gallimore, Pamela S. Tsang
Design Of Revising Proximity Between Space And Time Cues On Flight Deck Displays To Support Nextgen – The First Phase, Chang-Geun Oh, Jennie J. Gallimore, Pamela S. Tsang
International Journal of Aviation, Aeronautics, and Aerospace
The objective of this study is to develop and evaluate novel display formats to support RTA operations for near to midterm NextGen. Traditional cockpit displays separate space and time information in distant display sources in heterogeneous formats (graphics vs. text). This design composition may cause potential pilot errors when required time of arrival (RTA) obligations are imposed at every waypoint in NextGen. Pilots were randomly assigned to four different display conditions in a simulator – one traditional display with distant space and time cues, and three novel displays with close spatial proximity between the two cues. In the first phase …
Design Of Revising Proximity Between Space And Time Cues On Flight Deck Displays To Support Nextgen – The Second Phase, Chang-Geun Oh, Jennie J. Gallimore, Pamela S. Tsang
Design Of Revising Proximity Between Space And Time Cues On Flight Deck Displays To Support Nextgen – The Second Phase, Chang-Geun Oh, Jennie J. Gallimore, Pamela S. Tsang
International Journal of Aviation, Aeronautics, and Aerospace
The prior first phase of this study investigated the effectiveness of new design of flight deck display for required time of arrival operation of NextGen by collecting objective query response data during autopilot flights and subjective data about the perception between display condition and situation awareness level. To evaluate pilots’ mental workload during the operations when they interacted with novel flight deck display design, this second phase provided pilots with simulation flight tasks arriving at four successive waypoints on time in the same display conditions as the first phase and asked them to rate their mental workload ratings. The workload …
Evaluating The Effect Of Turbulence On Aircraft During Landing And Take-Off Phases, Anthony O'Connor, Derek Kearney
Evaluating The Effect Of Turbulence On Aircraft During Landing And Take-Off Phases, Anthony O'Connor, Derek Kearney
Articles
— Low level wind shear and turbulence present a serious safety risk to aircraft during the approach, landing and take-off phases. Low level wind shear has been identified as one of the primary factors for aircraft go-arounds and aborted landings. During any given year, wind shear occurs thousands of times at airports around the world, affecting the arrival and departure of aircraft. This paper has quantified the direct cost of flight Go-arounds. This paper will show the potential savings to the aviation industry. This paper will argue that a solution to the problem of forecasting low level wind shear and …
Application Of Improved Fast Dynamic Allan Variance For The Characterization Of Mems Gyroscope On Uav, Qian Zhang, Xueyun Wang, Shiqian Wang, Chaoying Pei
Application Of Improved Fast Dynamic Allan Variance For The Characterization Of Mems Gyroscope On Uav, Qian Zhang, Xueyun Wang, Shiqian Wang, Chaoying Pei
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Microelectromechanical systems (MEMS) are core components in unmanned aerial vehicles (UAV). The precision of MEMS sensors is very important when the GPS signal is invalid. However, the precision and performance of MEMS sensors will be degraded by the changing of environment. Therefore, estimation and identification of the various noise terms existing in MEMS sensors are deemed to be necessary. The Allan variance is a common and standard method to analyze MEMS sensors, but it cannot be used to analyze the dynamic characteristics. The dynamic Allan variance (DAVAR) is a sliding version of the Allan variance. It is a practical tool …
Boundary-Layer Separation Control Using Laser-Induced Air Breakdown, Alfram Bright, Nathan Tichenor, Kevin Kremeyer, Richard Wlezien
Boundary-Layer Separation Control Using Laser-Induced Air Breakdown, Alfram Bright, Nathan Tichenor, Kevin Kremeyer, Richard Wlezien
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Modification of the flow separation characteristics of a laminar airfoil using a remotely located high-power laser was experimentally investigated in a low-speed, low-turbulence wind tunnel. A laminar airfoil model (chord length of 500 mm) was designed and fabricated to emulate the flight characteristics of a small aircraft. At 0 deg angle of attack, the airfoil model was determined to have an incipient laminar separation bubble on its lifting surface between 67 and 80% chord. A strong laser-induced breakdown was generated 2 mm upstream of the leading edge by focusing a collimated beam emitted from a 900 mW laser at 1064 …
Investigation Of Additively Manufactured Polymer And Transparent Polymer Composites, Gregory Taylor
Investigation Of Additively Manufactured Polymer And Transparent Polymer Composites, Gregory Taylor
Doctoral Dissertations
"The objective of this study is an investigation of both the characterization of fused deposition modeling (FDM) of polymer thermoplastics and the manufacture of glass-reinforced transparent composites. The flexural behavior and fracture toughness of FDM parts are critical for the evaluation and optimization of both material and process. This study focuses on the performance of FDM Ultem 1010 specimens intended to be used as composite tooling due the material's high heat resistance. A three-point bend test is performed for flexure properties while a single edge notch bend test is performed for fracture toughness. For each of the tests, the build …
Including Topographical Effects In Slant-Range Modeling, Kari C. Ward, Kyle J. Demarsy
Including Topographical Effects In Slant-Range Modeling, Kari C. Ward, Kyle J. Demarsy
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Spacecraft descent-to-landing navigation often includes the use of a slant-range measurement, the distance from the spacecraft to a surface along the off-nadir pointing direction of the sensor. Modeling a slant range sensor requires a reference surface, approximations of which include spherical and ellipsoidal surfaces, spherical harmonic models, and topographical maps based on prior reconnaissance data. For the spherical and ellipsoidal reference surfaces, a closed-form solution of the slant-range measurement exists. However, these approaches are inaccurate with respect to the true surface. This paper develops a method to implement digital elevation maps of a given surface to create a topography-based model …
Electric Solid Propellant Ablation In A Pulsed Electric Thruster, Matthew S. Glascock, Joshua L. Rovey
Electric Solid Propellant Ablation In A Pulsed Electric Thruster, Matthew S. Glascock, Joshua L. Rovey
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Electric solid propellants are advanced solid chemical rocket propellant that can be controlled (ignited, throttled and extinguished) with electric current. Work reported here focuses on application of electric solid propellant in a pulsed electric thruster similar to a pulsed plasma thruster. In the future it may be possible to develop a dual-mode electric solid propellant thruster that is switchable between steady applied electric current chemical mode and pulsed alternating electric current electric mode. Results presented here use a laboratory test thruster to create an arc discharge of 5-20 J per pulse in a cylindrical cavity of propellant. Results for Teflon …
Square-Root Consider Filters With Hyperbolic Householder Reflections, James S. Mccabe, Kyle J. De Mars
Square-Root Consider Filters With Hyperbolic Householder Reflections, James S. Mccabe, Kyle J. De Mars
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Maintaining positive definiteness of a filter's error covariance estimate is of paramount importance to any stable and reliable estimation scheme. Two widely used methods for protecting a filter from loss of positive-definiteness are that of consider filtering and square-root filtering. Despite their widespread use in estimation applications, a filtering methodology that combines the two techniques has yet to be presented in a unified, streamlined architecture. This paper develops a new approach to square-root filtering using hyperbolic Householder reflections. A specialization of the method is considered to permit computationally efficient applications, and a numerical example pertaining to a ballistic reentry is …
Set-Theoretic Model Reference Adaptive Control Of A Generic Transport Model, Ehsan Arabi, Tansel Yucelen, Nhan T. Nguyen
Set-Theoretic Model Reference Adaptive Control Of A Generic Transport Model, Ehsan Arabi, Tansel Yucelen, Nhan T. Nguyen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper illustrates an application of a recently developed set-theoretic model reference adaptive control architecture on a generic transport model developed by NASA. The set- theoretic model reference adaptive control allows the system error bound between the state of an uncertain dynamical system and the state of a given reference model to be less than a-priori, user-defined worst-case performance bound. Thus, it has the capability to enforce strict performance guarantees to the adaptively controlled uncertain dynamical systems. specifically, after designing set-theoretic adaptive controllers for both longitudinal and lateral-directional dynamics here, the efficacy of this architecture is illustrated on the NASA …
Linear Burn Rate Of Monopropellant For Multi-Mode Micropropulsion, Alex J. Mundahl, Steven P. Berg, Joshua L. Rovey
Linear Burn Rate Of Monopropellant For Multi-Mode Micropropulsion, Alex J. Mundahl, Steven P. Berg, Joshua L. Rovey
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Multi-mode micro propulsion is a technology that can enable rapidly composable small satellites with unprecedented mission flexibility. To maximize mission flexibility a multi-mode micro propulsion monopropellant must be shared between the chemical and electric propulsion modes. Previous research has identified a promising monopropellant that is both readily catalytically exothermically decomposed (chemical mode) and electro sprayable (electric mode). In this work the linear burn rate of this monopropellant is determined and used to aid the design of a microtube catalytic chemical thruster. Experiments with a pressurized fixed volume reactor are used to determine the linear burn rate. Benchmark experiments use a …
Electrospray Mass Spectroscopy Of A Han-Based Monopropellant, Mitchell J. Wainwright, Joshua L. Rovey, Shawn W. Miller, Benjamin D. Prince, Steven P. Berg
Electrospray Mass Spectroscopy Of A Han-Based Monopropellant, Mitchell J. Wainwright, Joshua L. Rovey, Shawn W. Miller, Benjamin D. Prince, Steven P. Berg
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A mixture of [Emim][EtSO4]-HAN is a potential propellant suitable in a multi-mode chemical-electric microtube-electrospray micro propulsion system. This paper reports experimental mass spectrum results for this liquid when electro sprayed in a 50 μm capillary emitter. Mass spectra from 0-600 amu were obtained over a variety of angles and flow rates from 2 pL/sec to 3 nL/sec in both cation and anion extraction mode. Effects of flow rate and angular orientation on the spectra agree well with literature. Results show at least three of the four monomer species are emitted, along with numerous other species, some of which have been …
Efficient Inverse Design Of Transonic Airfoils Using Variable-Resolution Models And Manifold Mapping, Xiaosong Du, Leifur Leifsson, Slawomir Koziel
Efficient Inverse Design Of Transonic Airfoils Using Variable-Resolution Models And Manifold Mapping, Xiaosong Du, Leifur Leifsson, Slawomir Koziel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents an efficient approach for simulation-based inverse design of airfoil shapes using variable-fidelity computational fluid dynamics models and manifold mapping (MM). Inverse design involves determining an airfoil shape fulfilling a given target performance characteristic. In particular, the pressure coefficient distribution is typically used in aerodynamic inverse design. Such a task can be challenging when using computationally expensive simulations. In the context of local optimization, the MM technique searches for a new design in the vicinity of the current design by constructing a fast multi-fidelity model, which is setup by the available evaluations of each of the high- and …
Thermal Analysis And Control Of Small Satellites In Low Earth Orbit, Katelyn Elizabeth Boushon
Thermal Analysis And Control Of Small Satellites In Low Earth Orbit, Katelyn Elizabeth Boushon
Masters Theses
"Small satellites are becoming more popular in the space sector, primarily due to their lower cost and shorter development time. Much of the information available about satellite thermal analysis and control refers to larger spacecraft. Sorting through this information to find the practices specifically applicable for small satellites can be a daunting task, particularly for inexperienced engineers. This thesis study is intended to inform the reader about basic thermal control and analysis methods that relate specifically to small satellites in low Earth orbit. A case study involving a satellite designed by the Missouri University of Science and Technology Satellite Research …
Characterization Of Ionic Liquid Monopropellants For A Multi-Mode Propulsion System, Alex J. Mundahl
Characterization Of Ionic Liquid Monopropellants For A Multi-Mode Propulsion System, Alex J. Mundahl
Masters Theses
"Multi-mode micropropulsion is a potential game-changing technology enabling rapidly composable small satellites with unprecedented mission flexibility. Maximum mission flexibility requires one shared propellant between the chemical and electric systems. A deep eutectic 1:2 molar ratio mixture of choline-nitrate and glycerol ([Cho][NO3] - glycerol) is investigated as a fuel component in a binary mixture propellant for such a multi-mode micropropulsion. Specifically, binary mixtures of the novel ionic liquid fuel with hydroxyl-ammonium nitrate (HAN) and ammonium nitrate (AN) are considered and compared against the previously investigated propellant [Emim][EtSO4]-HAN. Chemical rocket performance simulations predict this new propellant to have …
Effects Of Terrain-Based Altimetry On Navigation Performance, Kenneth Michael Kratzer
Effects Of Terrain-Based Altimetry On Navigation Performance, Kenneth Michael Kratzer
Masters Theses
"Navigation filters used during an entry, descent, and landing scenario often receive measurements related to the terrain over which the vehicle is traversing. Models of the terrain can be presented in varying degrees of fidelity, providing increasingly realistic and accurate models of the surface. While it is ideal to provide the filter with the most realistic model possible, the performance is limited by the strict nature of the real time scenario. Therefore, it is of interest to determine what level of fidelity is necessary to achieve an accurate filtering solution. Determining how best to incorporate terrain-related data into navigation solutions …
Design And Evaluation Of Novel Attitude Estimation System Using Mems Sensors For Indoor Uas, Joshua Bruce Milam
Design And Evaluation Of Novel Attitude Estimation System Using Mems Sensors For Indoor Uas, Joshua Bruce Milam
Graduate Theses, Dissertations, and Problem Reports (ETD)
Most small unmanned aerial systems in use today, employ extended Kalman filter sensor fusion algorithms in order to provide accurate estimations of attitude or orientation. These complex algorithms use measurements from GPS receivers and magnetometer sensors that can be rendered useless in GPS denied environments or areas of significant magnetic interference, such as inside buildings or other structures. The complexity of these algorithms makes them inaccessible for some researchers and hobbyists who wish to code their own attitude estimation algorithms. This complexity is also computationally expensive and requires processors that are powerful enough to operate the algorithms along with any …
Thermal-Fatigue And Thermo-Mechanical Equivalence For Transverse Cracking Evolution In Laminated Composites, Javier Cabrera Barbero
Thermal-Fatigue And Thermo-Mechanical Equivalence For Transverse Cracking Evolution In Laminated Composites, Javier Cabrera Barbero
Graduate Theses, Dissertations, and Problem Reports (ETD)
Carbon fiber reinforced plastics (CFRP) are potential materials for many aerospace and aeronautical applications due to their high specif strength/weight and a low coeffcient of thermal expansion (CTE) resulting in a high long-term stability. Among candidate structures, the re-entry reusable launch vehicles (RLV), the fuel oxidant storage and transportation at cryogenic temperature, space satellites, and aircraft structure (frame, wings, etc...) can be highlighted. However, CFRP are prone to internal damage as a result of high residual stresses and thermal fatigue loading. In this study, micro-cracking damage evolution in laminated composites subjected to monotonic cooling and thermal cyclic loads is developed …
Crop Height Estimation With Unmanned Aerial Vehicles, Carrick Detweiler, David Anthony, Sebastian Elbaum
Crop Height Estimation With Unmanned Aerial Vehicles, Carrick Detweiler, David Anthony, Sebastian Elbaum
School of Computing: Faculty Publications
An unmanned aerial vehicle (UAV) can be configured for crop height estimation. In some examples, the UAV includes an aerial propulsion system, a laser scanner configured to face downwards while the UAV is in flight, and a control system. The laser scanner is configured to scan through a two-dimensional scan angle and is characterized by a maxi mum range. The control system causes the UAV to fly over an agricultural field and maintain, using the aerial propulsion system and the laser scanner, a distance between the UAV and a top of crops in the agricultural field to within a programmed …