Aerospace Engineering Commons^™

Design And Validation Of Pressure Based Flow Rate Soft Sensor For Freeze-Drying, Pasita Pibulchinda, Tong Zhu, Vaibhav Kshirsagar, Alina A. Alexeenko

The Summer Undergraduate Research Fellowship (SURF) Symposium

Lyophilization or freeze drying is a process of removing water by sublimation. It is commonly used to extend the shelf life of drugs in the pharmaceutical industry. Because the process is costly and time consuming, precise and efficient pressure, temperature control and drying time estimation are required. It is the goal of freeze-drying to run at maximum capacity while staying within the safe zone by carefully controlling the sublimation rate. Currently, real time estimation of sublimation rate is still challenging. The technique available called Tunable diode laser absorption spectroscopy (TDLAS) is invasive, and requires major modifications. The current study focuses …

Using P-Band Signals Of Opportunity Radio Waves For Root Zone Soil Moisture Remote Sensing, Phillip H. Lipinski, Benjamin R. Nold, James L. Garrison

The Summer Undergraduate Research Fellowship (SURF) Symposium

Retrieval of Root Zone Soil Moisture (RZSM) is important for understanding the carbon cycle for use in climate change research as well as meteorology, hydrology, and precision agriculture studies. A current method of remote sensing, GNSS-R uses GPS signals to measure soil moisture content and vegetation biomass, but it is limited to 3-5 cm of soil penetration depth. Signals of Opportunity (SoOp) has emerged as an extension of GNSS-R remote sensing using communication signals. P-band communication signals (370 MHz) will be studied as an improved method of remote sensing of RZSM. P-band offers numerous advantages over GNSS-R, including stronger signal …

Additive Manufacturing Of High Solids Loading Hybrid Rocket Fuel Grains, Stephen P. Johnson, Michael Baier, Ibrahim E. Gunduz, Steven F. Son

The Summer Undergraduate Research Fellowship (SURF) Symposium

Hybrid rocket motors offer many of the benefits of both liquid and solid rocket systems. Like liquid engines, hybrid rocket motors are able to be throttled, can be stopped and restarted, and are safer than solid rocket motors since the fuel and oxidizer are in different physical states. Hybrid rocket motors are similar to solid motors in that they are relatively simple and have a high density-specific impulse. One of the major drawbacks of hybrid rocket motors is a slower burning rate than solid rocket motors. Complex port geometries provide greater burning surface area to compensate for lower burning rates …

Using High Resolution Images To Investigate Fatigue Crack Initiation Of Alloys At The Microstructural Level, Michael P. Reinhold, Alberto Mello, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microstructural features within a material dictate the material’s mechanical behavior and lead to localized strains as the sample is deformed. In order to further understand structural failure, an improved understanding of how microstructural features influence failure is necessary. Fatigue is one common mode of failure for aerospace applications, and a better understanding of the conditions of crack initiation can provide information that ultimately may increase longevity of aerospace systems. This paper investigates the hypothesis that fatigue crack initiation for a cyclically loaded sample is correlated to areas of higher localized strain. The experiment was conducted using a Ti-6Al-4V sample subjected …

Operation Of The T-100 Hall Effect Thruster, Glynn Smith, Omar Dary, Alexey Shashurin

The Summer Undergraduate Research Fellowship (SURF) Symposium

The introduction of Hall Effect Thrusters from the former Soviet Union to the United States generated considerable interest in using the propulsion system aboard Western spacecraft. The established programs evaluated the SPT-100, and TAL-55 Hall Effect Thrusters for efficiency, lifetime, and performance characteristics. The T-100 model garnered only minor interest during this time compared with the same generation counterparts, the SPT-100, and TAL-55. This gap in knowledge on the efficiency, and performance of the T-100 warrants investigation into the design, and operation of the thruster. Operational characteristics will be measured on a restored T-100 Hall Thruster, using argon as a …

Hazard Assessment Of Meteoroid Impact For The Design Of Lunar Habitats, Herta Paola Montoya, Shirley Dyke, Julio A. Ramirez, Antonio Bobet, H. Jay Melosh, Daniel Gomez

The Summer Undergraduate Research Fellowship (SURF) Symposium

The design of self-sustaining lunar habitats is a challenge primarily due to the Moon’s lack of atmospheric protection and hazardous environment. To assure safe habitats that will lead to further lunar and space exploration, it is necessary to assess the different hazards faced on the Moon such as meteoroid impacts, extreme temperatures, and radiation. In particular, meteoroids pose a risk to lunar structures due to their high frequency of occurrence and hypervelocity impact. Continuous meteoroid impacts can harm structural elements and vital equipment compromising the well-being of lunar inhabitants. This study is focused on the hazard conceptualization and quantification of …

Hybrid Buoyant Aircraft: Future Stol Aircraft For Interconnectivity Of The Malaysian Islands, Anwar Ul Haque, Waqar Asrar, Ashraf Ali Omar, Erwin Sulaeman, Jaffar Syed Mohamed Ali

Journal of Aviation Technology and Engineering

Hybrid buoyant aircraft are new to the arena of air travel. They have the potential to boost the industry by leveraging new emerging lighter-than-air (LTA) and heavier-than-air (HTA) technologies. Hybrid buoyant aircraft are possible substitutes for jet and turbo-propeller aircraft currently utilized in aviation, and this manuscript is a country-specific (Malaysia) analysis to determine their potential market, assessing the tourism, business, agricultural, and airport transfer needs of such vehicles. A political, economic, social, and technological factors (PEST) analysis was also conducted to determine the impact of PEST parameters on the development of buoyant aircraft and to assess all existing problems …

Modeling And Computation Of The Maximum Braking Energy Speed For Transport Category Airplanes, Nihad E. Daidzic

Journal of Aviation Technology and Engineering

Transport-category or FAR/CS 25 certified airplanes may occasionally become braking energy capacity limited. Such limitation may exist when heavy airplanes are departing airports at high-density altitudes, on relatively long runways, and/or possibly with some tailwind component. A maximum braking energy VMBE speed exists which may limit the maximum allowable takeoff decision/action speed V1. The ever-existing possibility of high-speed rejected takeoff in such conditions may also limit the airplane gross weight for declared available distances. To gain deeper insights and acquire better understanding of the topic, a theoretical model of the maximum braking energy and the related VMBE speed for T-category …

Multi-Stage Nozzle-Shape Optimization For Pulsed Hydrogen-Air Detonation Combustor, Francesco Ornano, James Braun, Bayindir H. Saracoglu, Guillermo Paniagua

School of Aeronautics and Astronautics Faculty Publications

hermal engines based on pressure gain combustion offer new opportunities to generate thrust with enhanced efficiency and relatively simple machinery. The sudden expansion of detonation products from a single-opening tube yields thrust, although this is suboptimal. In this article, we present the complete design optimization strategy for nozzles exposed to detonation pulses, combining unsteady Reynolds-averaged Navier-Stokes solvers with the accurate modeling of the combustion process. The parameterized shape of the nozzle is optimized using a differential evolution algorithm to maxi­ mize the force at the nozzle exhaust. The design of experiments begins with a first optimization considering steady-flow conditions, subsequently …

Interplanetary Mission Design With Applications To Guidance And Optimal Control Of Aero-Assisted Trajectories, Peter J. Edelman

Open Access Dissertations

A method for finding optimal aerogravity-assist tours of the solar system is developed using indirect methods. Two cost functionals are used in the optimization; finding the minimum required maximum lift-to-drag ratio, with and without a convective heating-rate path constraint, and the path which provides the minimum total stagnation point convective heat load. It is found that using present or near-future thermal protection system materials will suffice for certain aerogravity assist trajectories at Mars. Minimum heat load optimal trajectories are found for aerocapture maneuvers at Uranus and Neptune. With a large radius, and short rotational periods, atmospheric rotation must be taken …

Secondary Instabilities Of Hypersonic Stationary Crossflow Waves, Joshua Benjamin Edelman

Open Access Theses

A sharp, circular 7° half-angle cone was tested in the Boeing/AFOSR Mach-6 Quiet Tunnel at 6° angle of attack. Using a variety of roughness configurations, measurements were made using temperature-sensitive paint (TSP) and fast pressure sensors. High-frequency secondary instabilities of the stationary crossflow waves were detected near the aft end of the cone, from 110° to 163° from the windward ray.

At least two frequency bands of the secondary instabilities were measured. The secondary instabilities have high coherence between upstream and downstream sensor pairs. In addition, the amplitudes of the instabilities increase with the addition of roughness elements near the …

Trajectory Optimization Using Indirect Methods And Parametric Scramjet Cycle Analysis, Joseph Williams

Open Access Theses

This study investigates the solution of time sensitive regional strike trajectories for hypersonic missiles. This minimum time trajectory is suspected to be best performed by scramjet powered hypersonic missiles which creates strong coupled interaction between the flight dynamics and the performance of the engine. Comprehensive engine models are necessary to gain better insight into scramjet propulsion. Separately, robust and comprehensive trajectory analysis provides references for vehicles to fly along. However, additional observation and understanding is obtained by integrating the propulsion model inside the trajectory framework. Going beyond curve fitted thrusting models, an integrated scramjet cycle analysis offers rapid trade studies …

Numerical Investigation Of Crossflow Instability On The Hifire-5, Matthew T. Lakebrink

Open Access Dissertations

Stability analysis was performed with the Langley Stability and Transition Analysis Code (LASTRAC) on a 38.1% scale model of the HIFiRE-5 elliptic-cone forebody to study crossflow-induced transition in hypersonic boundary layers. A resolution study consisting of three grids (30e6, 45e6, and 91e6 points) indicated that the fine grid was sufficiently resolved. Results were largely insensitive to grid resolution over the acreage and near the attachment line. The percent variation in second-mode properties along the semi-minor axis was less than 1% between the medium and fine grids. The variation in crossflow-wave properties was less than 0.04% between the medium and fine …

Assessing Fuel Burn Inefficiencies In Oceanic Airspace, Stephen Builta

Open Access Theses

Increasing the efficiency of aircraft operations offers a shorter term solution to decreasing aircraft fuel burn than fleet replacement. By estimating the current airspace inefficiency, we can get an idea of the upper limit of savings. Oceanic airspace presents a unique opportunity for savings due to increased separation differences vs. overland flight.

We assess fuel burn inefficiency by comparing estimated fuel burn for real world flights with the estimated optimal fuel burn. For computing fuel burn, we use the Base of Aircraft Data (BADA) with corrections based on research by Yoder (2005). Our fuel burn results show general agreement with …

Mechanism Of Shot Peening Enhancement For The Fatigue Performance Of Aa7050-T7451, Daniel James Chadwick

Open Access Theses

Shot peening is a dynamic cold working process involving the impingement of peening media onto a substrate surface. Shot peening is commonly employed as a surface treatment technique within the aerospace industry during manufacturing, in order to improve fatigue performance of structural components. The compressive residual stress induced during shot peening is understood to result in fatigue crack growth retardation, improving the performance of shot peened components. However, shot peening is a compromise between the benefit of inducing a compressive residual stress and causing detrimental surface damage. Due to the relatively soft nature of AA7050-T7451, shot peening can result in …

Flammability Limits Of Alternative Aviation Fuels, Ang Li

Open Access Theses

Alternative aviation fuels are being developed recently to partially replace the limited resources of traditional liquid fuels in the aviation industry. The fire-safety properties of these fuels, however, are unknown. Especially, the flammability limit of a fuel is a crucial parameter. The present work focuses on measurements of concentration and temperature flammability limits of four pure hydrocarbon fuels, as well as traditional and alternative aviation fuels, including Jet-A, HEFA, SIP, and FT-S8. The lower and upper concentration flammability limits of these selected fuels were determined under specific temperatures and pressures. An experiment including a customized power supply system to generate …

Characterization Of A Hypersonic Quiet Wind Tunnel Nozzle, Cameron J. Sweeney

Open Access Theses

The Boeing/AFOSR Mach-6 Quiet Tunnel at Purdue University has been able to achieve low-disturbance flows at high Reynolds numbers for approximately ten years. The flow in the nozzle was last characterized in 2010. However, researchers have noted that the performance of the nozzle has changed in the intervening years. Understand ing the tunnel characteristics is critical for the hypersonic boundary-layer transition research performed at the facility and any change in performance could have signif icant effects on research performed at the facility. Pitot probe measurements were made using Kulite and PCB pressure transducers to quantify the performance changes since characterization …

Helical Strakes On High Mast Lighting Towers And Their Effect On Vortex Shedding Lock-In, Ayah Zahour

Open Access Theses

An experimental study on the effect of helical strakes on vortex induced vibrations and the lock-in phenomenon in High Mast Lighting Towers (HMLTs) is investigated. Two multi-sided tapered scaled models are clamped in place in a subsonic wind tunnel that is equipped with a hot-wire sensor and a traverse mechanism. The shedding frequency data is collected for the models with and without helically patterned strakes with the use of two different ropes. The responses of the tower models, for a Reynolds number of 44, 000, are compared and discussed under different configurations including: two directions of the model with respect …

Metrics Of Critical Pair Identification, Zixu Zhang

Open Access Theses

Critical Pair Identification works as a potential assistive tool for human air traffic controllers by identifying potentially dangerous situations that are not detected by proposed automated separation assurance systems. This concept specifically considers conflicts that might arise if aircraft unexpectedly deviate from their planned flight path in the near future. Five metrics of the critical pair concept, Critical Pair Count, Time to Risk Exposure, Lead Time, Risk Exposure Duration and Blunder Sensitivity Index, have been developed and mathematically defined to characterize the safety level of an aircraft pair or a volume of air space. Algorithm that computes proposed metrics is …

Analysis Of Composite Plates By Using Mechanics Of Structure Genome And Comparison With Ansys, Banghua Zhao

Open Access Theses

Motivated by a recently discovered concept, Structure Genome (SG) which is defined as the smallest mathematical building block of a structure, a new approach named Mechanics of Structure Genome (MSG) to model and analyze composite plates is introduced. MSG is implemented in a general-purpose code named SwiftComp™, which provides the constitutive models needed in structural analysis by homogenization and pointwise local fields by dehomogenization. To improve the user friendliness of SwiftComp™, a simple graphic user interface (GUI) based on ANSYS Mechanical APDL platform, called ANSYS-SwiftComp GUI is developed, which provides a convenient way to create some common SG models or …

Free Edge Stress Analysis Of Laminated Structures With Arbitrary Cross Sections Using Mechanics Of Structure Genome, Lingxuan Zhou

Open Access Theses

Composite laminates have been increasingly used in advanced structural applications, due to their excellent strength-to-weight properties and considerable flexibility on designing with respect to the laminate layup. However, the heterogeneity and anisotropy of composite laminates have brought many challenges for analysis and numerous researches have been devoted in this field. A well known problem which has been studied intensively is the so-called free-edge problem. It states that due to the mismatch in elastic properties of adjacent layers, full-scale three-dimensional (3D) and highly concentrated stress fields will occur in the vicinity of the free edges. The interlaminar stresses grow very rapidly …

Modeling Methods For Merging Computational And Experimental Aerodynamic Pressure Data, Jacob Courtney Haderlie

Open Access Dissertations

This research describes a process to model surface pressure data sets as a function of wing geometry from computational and wind tunnel sources and then merge them into a single predicted value. The described merging process will enable engineers to integrate these data sets with the goal of utilizing the advantages of each data source while overcoming the limitations of both; this provides a single, combined data set to support analysis and design. The main challenge with this process is accurately representing each data source everywhere on the wing. Additionally, this effort demonstrates methods to model wind tunnel pressure data …

Gravity-Assist Trajectories To Venus, Mars, And The Ice Giants: Mission Design With Human And Robotic Applications, Kyle M. Hughes

Open Access Dissertations

Gravity-assist trajectories to Uranus and Neptune are found (with the allowance of impulsive maneuvers using chemical propulsion) for launch dates ranging from 2024 to 2038 for Uranus and 2020 to 2070 for Neptune. Solutions are found using a patched conic model with analytical ephemeris via the Satellite Tour Design Program (STOUR), originally developed at the Jet Propulsion Laboratory (JPL). Delivered payload mass is computed for all solutions for select launch vehicles, and attractive solutions are identified as those that deliver a specified amount of payload mass into orbit at the target body in minimum time. The best cases for each …

Development Of Inverse Methods For Reconstruction Of Flight Environments On Ablators, A. Brandon Oliver

Open Access Dissertations

Obtaining measurements of flight environments on ablative heatshields is both critical for spacecraft development and extremely challenging due to the harsh heating environment and surface recession. Thermocouples installed several millimeters below the surface are commonly used to measure the heatshield temperature response, but an ill-posed inverse heat conduction problem must be solved to reconstruct the surface heating environment from the embedded thermocouple measurements. The material properties of typical ablators make the reconstruction process more challenging when the measurements are deep, but measurements often must be located deep to allow for surface recession. Compounding the complexity of the surface reconstruction problem, …

A New Approach To Modeling Aviation Accidents, Arjun Harsha Rao

Open Access Dissertations

General Aviation (GA) is a catchall term for all aircraft operations in the US that are not categorized as commercial operations or military flights. GA aircraft account for almost 97% of the US civil aviation fleet. Unfortunately, GA flights have a much higher fatal accident rate than commercial operations. Recent estimates by the Federal Aviation Administration (FAA) showed that the GA fatal accident rate has remained relatively unchanged between 2010 and 2015, with 1566 fatal accidents accounting for 2650 fatalities. Several research efforts have been directed towards betters understanding the causes of GA accidents. Many of these efforts use National …

Simulation Investigation Of Temperature Distribution In Large Aluminium Panel During Autoclave Age Forming Process, Yongqian Xu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Multi-Dome Forming Of A Ti–Al–Mn Alloy, Sergey Aksenov, Aleksey Kolesnikov, Ivan Zakhariev

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

3d Fe Modelling Of Die Stress And Wear In Non-Isothermal Forging Of Ti–6al–4v Turbine Blade, Shiyuan Luo, Dahu Zhu, Lin Hua, Dongsheng Qian, Sijie Yan

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Assessment Of High Cycle Fatigue Crack Growth Under Different Stages Based On Crystal Plasticity Modeling, Duoqi Shi, Shiwei Han, Xiaoguang Yang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Development Of Functional Requirements For A High-Capacity Airspace System, Noel J. Colon, Jeongjoon Boo, Steven J. Landry

The Summer Undergraduate Research Fellowship (SURF) Symposium

NASA along with other researchers visualizes a future where more aircraft will transport passengers or goods around the world. Thus, they envision increasing air capacity from 10 to 100 times more than the current system without any reduction in efficiency or safety. Many models are being proposed that comply with the necessary requirements to form part of the method needed. However, knowing which of the proposed methods have the most desirable characteristics, such as efficiency and safety, are yet to be determined. For this reason, a standardized method to compare and assess them has to be developed, since is not …