Engineering Commons^™

A Study Of Ship Airwakes Using Dual Plane Stereoscopic Piv, Guillermo Mazzilli

Doctoral Dissertations and Master's Theses

The airwake of a model Simple Frigate Shape 2 (SFS2) was studied in a low-speed wind tunnel. This airwake was measured using a novel time-dependent, dual plane, stereoscopic particle image velocimetry approach. Two flow planes over the flight deck, one parallel and one perpendicular to the free-stream were simultaneously measured. Measurements were carried out over four such pairs of streamwise-spanwise plane combinations. Additionally, the airwake with and without a simulated atmospheric boundary layer (sABL) was studied. The synchronicity of the measurements were taken advantage of to carry out conditional averages of the flow field to isolate and study certain flow …

Machine Learning To Predict Warhead Fragmentation In-Flight Behavior From Static Data, Katharine Larsen

Doctoral Dissertations and Master's Theses

Accurate characterization of fragment fly-out properties from high-speed warhead detonations is essential for estimation of collateral damage and lethality for a given weapon. Real warhead dynamic detonation tests are rare, costly, and often unrealizable with current technology, leaving fragmentation experiments limited to static arena tests and numerical simulations. Stereoscopic imaging techniques can now provide static arena tests with time-dependent tracks of individual fragments, each with characteristics such as fragment IDs and their respective position vector. Simulation methods can account for the dynamic case but can exclude relevant dynamics experienced in real-life warhead detonations. This research leverages machine learning methodologies to …

Passive, Self-Healable, Dielectric Elastomers For Structural Health Monitoring, Nicholas Smith

Doctoral Dissertations and Master's Theses

NASA maintains the ability to track a large majority of objects in Earth’s orbit, however lack the ability to track objects smaller than five centimeters in diameter. These untrackable objects represent a significant danger to inflatable structures. This work seeks to synthesize and fabricate a self-healable, passive, dielectric elastomer impact sensor for structural health monitoring on inflatable space structures subject to impact by micrometeoroids and orbital debris. In a setting in which impact repairs can be extremely costly, the implementation of such a technology would not only alert personnel of such an event but would also serve to decrease the …

Assessment Of Iso-Ahola’S Theory Of Tourism Motivation On Willingness To Fly As A Point-To-Point Suborbital Space Tourist, Brian T. Musselman

Doctoral Dissertations and Master's Theses

Suborbital space tourism involves flight in an air vehicle to an altitude exceeding 100 kilometers (62 miles). This altitude is referred to as the Karman Line and the edge of space. Point-to-point space travel is transportation in an air vehicle where the vehicle flies around the earth in space to decrease the time to travel from one point on the earth’s surface to another point on the earth’s surface. The commercial space flight industry has a vision for point-to-point space travel.

The study aimed to assess the influence of the four dimensions of Iso-Ahola’s (1982) theory of tourism motivation on …

Predicting Defects In Laser Powder Bed Fusion Using In-Situ Thermal Imaging Data And Machine Learning, Sina Malakpour Estalaki, Cody S. Lough, Robert G. Landers, Edward C. Kinzel, Tengfei Luo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Variation in the local thermal history during the Laser Powder Bed Fusion (LPBF) process in Additive Manufacturing (AM) can cause micropore defects, which add to the uncertainty of the mechanical properties (e.g., fatigue life, tensile strength) of the built materials. In-situ sensing has been proposed for monitoring the AM process to minimize defects, but successful minimization requires establishing a quantitative relationship between the sensing data and the porosity, which is particularly challenging with a large number of variables (e.g., laser speed, power, scan path, powder property). Physics-based modeling can simulate such an in-situ sensing-porosity relationship, but it is computationally costly. …

Digital Twins In Advanced Manufacturing To Enhance Manufacturing Efficiency, Max Kirkpatrick

Theses and Dissertations

Digital Twins of manufacturing systems are an emerging tool for improvement, optimization, and monitoring of physical manufacturing systems. The idea of representing physical systems with digital depictions has been prevalent since the early days of Computer Aided Design (CAD), but recently the concept of a Digital Twin has been expanded to encapsulate more than just a digital model of a design. Instead, the Digital Twin offers a unique, comprehensive, and real-time toolset for analysis and improvement of physical systems. These tools can be used to improve system efficiency, perform “what-if” analyses, virtually commission manufacturing equipment, analyze system performance in real …

Machine Learning In Aerodynamic Shape Optimization, Jichao Li, Xiaosong Du, Joaquim R.R.A. Martins

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Machine learning (ML) has been increasingly used to aid aerodynamic shape optimization (ASO), thanks to the availability of aerodynamic data and continued developments in deep learning. We review the applications of ML in ASO to date and provide a perspective on the state-of-the-art and future directions. We first introduce conventional ASO and current challenges. Next, we introduce ML fundamentals and detail ML algorithms that have been successful in ASO. Then, we review ML applications to ASO addressing three aspects: compact geometric design space, fast aerodynamic analysis, and efficient optimization architecture. In addition to providing a comprehensive summary of the research, …

Understanding Unsteady Corner Separation Within Wing-Body Junction Flows, Paul G. Winner

Doctoral Dissertations and Master's Theses

Wing-body junction flows, formed at the interface between a wing and fuselage surface, are a complex, coupled, three-dimensional, turbulent flow field. This thesis focused on the unsteady corner separation that develops at the trailing edge of this wing-body junction under certain conditions. A NACA 0015 wing mounted on a flat plate at an angle of attack of 13°was used as the model junction flow field. The wing had an aspect ratio of 8 with a linear washout twist of 15°. The Reynolds number based on the wing chord was Re_c = 4.5 × 10⁵. Time-dependent stereoscopic particle …

Sme Coffee Hour: Human Factors: Dirty Dozennorms And Complacency, Linda Vee Weiland

Publications

Presentation about the relevance between communication, language, complacency and norms related to flight safety.

A Data Driven Modeling Approach For Store Distributed Load And Trajectory Prediction, Nicholas Peters

Doctoral Dissertations and Master's Theses

The task of achieving successful store separation from aircraft and spacecraft has historically been and continues to be, a critical issue for the aerospace industry. Whether it be from store-on-store wake interactions, store-parent body interactions or free stream turbulence, a failed case of store separation poses a serious risk to aircraft operators. Cases of failed store separation do not simply imply missing an intended target, but also bring the risk of collision with, and destruction of, the parent body vehicle. Given this risk, numerous well-tested procedures have been developed to help analyze store separation within the safe confines of wind …

Validation And Verification Of The Wray-Agarwal Turbulence And Algebraic Transition Models For 2d External Airfoil Flows, Dean Ryan-Simmons

McKelvey School of Engineering Graduate Student Theses & Dissertations

Validation and verification benchmark test cases are employed in computational fluid dynamics (CFD) to determine the best practices in application of various CFD tools. These cases focus on the geometry modeling, mesh generation, numerical algorithms, and turbulence models to ensure consistent and accurate numerical simulation of physical phenomena. Assessing model accuracy is essential to identify areas of improvement in various turbulence models. Flow past several symmetric NACA airfoils, namely NACA 0012, NACA 0015 and NACA 0018 are standard test cases for validating and evaluating turbulence models’ accuracy since the experimental data is available for these airfoils. Available wind tunnel data …

Pace Oci Short-Wave Infrared Detection Assembly Frequency-Dependent Linearity Characterization And Uncertainty Analysis, Kenneth J. Squire, Jacob Hedelius, David K. Moser, James Q. Peterson, Eric T. Gorman, Emily Kan, D. Brent Mott, Ulrik B. Gliese, Gerhard Meister

Space Dynamics Laboratory Publications

The Ocean Color Instrument (OCI), the primary payload of the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) observatory, will collect data to monitor the health of Earth’s oceans and atmosphere. The Short-Wave Infrared (SWIR) Detection Assembly (SDA) was built and characterized by the Utah State University Space Dynamics Laboratory (SDL) and is a subsystem of OCI. The SDA measures seven bands centered at 940, 1038, 1250, 1378, 1615, 2130, and 2260 nm, with standard- and high-gain varieties for the 1250 and 1615 nm bands, resulting in nine total detection configurations in the SWIR. The delivery of high-quality science data is critically …

Infrared Spectral Responses Of The Ocean Color Instrument (Oci) Pre-Assembly And Integration, Jacob K. Hedelius, Kenneth J. Squire, James Q. Peterson, Branimir Blagojević, Ulrik B. Gliese, Eric T. Gorman, David K. Moser, Zakk Rhodes, Pedro Sevilla, Gerhard Meister

Space Dynamics Laboratory Publications

Spectral characterizations were made of the Ocean Color Instrument (OCI) short-wave infrared (SWIR) Detection Subassembly (SDS) responses (940–2260 nm) prior to their integration. Using modulated output light from a Fourier transform spectrometer, the in-band relative spectral responses of the nine different configurations of SDSs were found along with out-of-band (OOB) sensitivity. From these spectral responses, the center wavelengths (λ₀), full widths at half of the maximum, full widths at 1% of the maximum, and OOB rejection ratios were determined. All spectral parameters are within requirements. There are 2–8 repeats of each configuration, and the 1 σ spread among …

Feasibility Of Low-Enriched Uranium Fueled Nuclear Thermal Propulsion In The Low-Thrust Region Below 16klbf, Samantha B. Rawlins, Dale L. Thomas

PRC-Affiliated Research

No abstract provided.

Turbine Cooling System With Energy Separation, James L. Rutledge, Matthew Fuqua, Carol M. Bryant

AFIT Patents

A method and system for cooling an engine and/or vehicle using energy separation is disclosed herein. An energy separation device is operable for separating a compressed gaseous coolant stream into a first relatively cooler coolant flow stream and a second relatively hotter coolant flow stream. The relative cooler coolant flow stream is directed to a first region requiring increased cooling and the relative hotter coolant flow stream is directed to a second region requiring lower cooling than the first region in the engine or vehicle.

A Machine Learning Framework For Automatic Speech Recognition In Air Traffic Control Using Word Level Binary Classification And Transcription, Fowad Shahid Sohail

Theses and Dissertations

Advances in Artificial Intelligence and Machine learning have enabled a variety of new technologies. One such technology is Automatic Speech Recognition (ASR), where a machine is given audio and transcribes the words that were spoken. ASR can be applied in a variety of domains to improve general usability and safety. One such domain is Air Traffic Control (ATC). ASR in ATC promises to improve safety in a mission critical environment. ASR models have historically required a large amount of clean training data. ATC environments are noisy and acquiring labeled data is a difficult, expertise dependent task. This thesis attempts to …

Design Of Composite Double-Slab Radar Absorbing Structures Using Forward, Inverse, And Tandem Neural Networks, Devin Nielsen, Juhyeong Lee, Young-Woo Nam

Mechanical and Aerospace Engineering Faculty Publications

The survivability and mission of a military aircraft is often designed with minimum radar cross section (RCS) to ensure its long-term operation and maintainability. To reduce aircraft’s RCS, a specially formulated Radar Absorbing Structures (RAS) is primarily applied to its external skins. A Ni-coated glass/epoxy composite is a recent RAS material system designed for decreasing the RCS for the X-band (8.2 – 12.4 GHz), while maintaining efficient and reliable structural performance to function as the skin of an aircraft. Experimentally measured and computationally predicted radar responses (i.e., return loss responses in specific frequency ranges) of multi-layered RASs are expensive and …

Hyper-Velocity Impact Performance Of Foldcore Sandwich Composites, Nathan Hoch, Chase Mortensen, Juhyeong Lee, Khari Harrison, Kalyan Raj Kota, Thomas Lacy

Mechanical and Aerospace Engineering Faculty Publications

A foldcore is a novel core made from a flat sheet of any material folded into a desired pattern. A foldcore sandwich composite (FSC) provides highly tailorable structural performance over conventional sandwich composites made with honeycomb or synthetic polymer foam cores. Foldcore design can be optimized to accommodate complex shapes and unit cell geometries suitable for protective shielding structures

This work aims to characterize hypervelocity impact (> 2000 m/s, HVI) response and corresponding damage morphologies of carbon fiber reinforced polymer (CFRP) FSCs. A series of normal (0° impact angle) and oblique (45° impact angle) HVI (~3km/s nominal projectile velocity) impact …

Predicting Stochastic Lightning Mechanical Damage Effects On Carbon Fiber Reinforced Polymer Matrix Composites, Juhyeong Lee, Syed Zulfiqar Hussain Shah

Mechanical and Aerospace Engineering Faculty Publications

Three stochastic air blast models are developed with spatially varying elastic properties and failure strengths for predicting lightning mechanical damage to AS4/3506 carbon/epoxy composites subjected to < 100 kA peak currents: (1) the conventional weapon effects program (CWP) model, (2) the coupled eulerianlagrangian (CEL) model, and (3) the smoothed-particle hydrodynamics (SPH) model. This work is an extension of our previous studies [1–4] that used deterministic air blast models for lightning mechanical damage prediction. Stochastic variations in composite material properties were generated using the Box-Muller transformation algorithm with the mean (i.e., room temperature experimental data) and their standard deviations (i.e., 10% of the mean herein as reference). The predicted dynamic responses and corresponding damage initiation prediction for composites under equivalent air blast loading were comparable for the deterministic and stochastic models. Overall, the domains with displacement, von-Mises stress, and damage initiation contours predicted in the stochastic models were somewhat sporadic and asymmetric along the fiber’s local orientation and varied intermittently. This suggests the significance of local property variations in lightning mechanical damage prediction. Thus, stochastic air blast models may provide a more accurate lightning mechanical damage approximation than traditional (deterministic) air blast models. All stochastic models proposed in this work demonstrated satisfactory accuracy compared to the baseline models, but required substantial computational time due to the random material model generation/assignment process, which needs to be optimized in future work.

Laser Ablation Of Cfrp Surfaces For Improving The Strength Of Bonded Scarf Composite Joints, Jassem Alyousef, Arief Yudhanto, Ran Tao, Gilles Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Repairing damaged composite parts using scarf technique requires a careful selection of treatment methods for composite surface. Laser treatment is one of the emerging techniques to treat the milled composite surface by unlocking various levels of morphological changes and, thus, optimizing joint strength. However, laser parameters, e.g., energy density (fluence), should be carefully determined to ensure the acceptable structural recovery. Here, the influence of CO2 laser with relatively high fluence (ablation effect) on the surface characteristics (roughness, morphology, wettability) and scarf joint strength with associated failure modes of unidirectional (UD) and quasi-isotropic (QI) carbon fiber-reinforced plastic (CFRP) laminates is studied. …

Effects Of Radiation Reabsorption On The Laminar Flame Speed And No Emission During Aviation Kerosene Combustion At Elevated Pressures, Shu Zheng, Hao Liu, Qing Li, Jiajian Zhu, Mingbo Sun, Bo Zhou, Ran Sui, Qiang Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Increasing attention has been paid on combustion stability and pollution emission of aviation kerosene due to the emerging interests on supersonic combustion scramjets. Whereas the vitiation component H2O introduced by hydrogen-fueled heaters in high-enthalpy vitiated air during ground experiments has a considerable influence on kerosene combustion, especially through its radiation effect, which needs to be further investigated. In this paper, the radiation reabsorption effects on laminar flame speeds and NO emissions during RP-3/H2O/O2/N2 combustion was assessed numerically over a wide range of equivalence ratio and pressure (ϕ = 0.7–1.4 and P = 1–15 atm) using detailed chemical and radiation models. …

Full Volume 13, Issue 1, Seyma Tufan

Space and Defense

No abstract provided.

Metallization Of Polymers And Composites: State-Of-The-Art Approaches, Ruslan Melentiev, Arief Yudhanto, Ran Tao, Todor Vuchkov, Gilles Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Polymers and their composites are widely used for designing structures in aerospace, automotive, electronic, sport industries due to their lightweight, cost, and processing advantages. However, the surface of polymeric materials typically exhibits intrinsic deficiencies, limiting their durability and functionalities, e.g., low wear resistance, low thermal and electrical conductivity, low adhesion, low bioactivity, low reflectiveness, and weak photochemical resistance. Polymer metallization is an emerging concept that addresses these deficiencies by forming a metallic skin on polymeric surfaces. Herein, the working principles, recent advances, challenges, functional capabilities, and applications of the state-of-the-art polymer metallization methods in the fields of additive manufacturing, coating …

Improved Additive Manufacturing Of Silicon Carbide Parts Via Pressureless Electric Field-Assisted Sintering, Adam Bratten, Ruoyu Chen, Joshua Rittenhouse, Ming-Chuan Leu, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

High solids loading silicon carbide (SiC)-based aqueous slurries containing only.5 wt. % organic additives were utilized to create specimens of various geometries via an extrusion-based additive manufacturing (AM) technique. Pressure less electric field-assisted sintering was performed to densify each specimen without deformation. The combination of these techniques produced parts with >98% relative density despite containing only 5 wt.% oxide sintering additives. After sintering, specimens contained only the α-SiC and yttrium aluminum perovskite phases. This suggests the evolution of a nonequilibrium yttrium aluminate phase, as well as transformation from β-SiC to α-SiC. The fabrication method presented in this work has advantages …

Finite Fatigue Life Prediction Of Additively Manufactured Aircraft Engine Turbine Blade With Respect To Internal Defect Size And Location, Daniel G. Miller

Theses and Dissertations

Current fatigue life modeling techniques with respect to defects emphasize the dependence on the defect size with respect to fatigue life, but does not account for the effects of where a defect might be located. This research outlines a process to include defect location into the model analysis for a more precise prediction of the number of cycles to failure and where the finial failure could occur within a component. The focus is on a turbine blade structure using IN718 subjected to a pure vibratory load. The basic model predicts component life using a stress map from the frequency analysis …

Mechanical Properties And Tension-Tension Fatigue Behavior Of A Novel Additively Manufactured Polymer Matrix Composite At Room And Elevated Temperature, Grayson M. Harber

Theses and Dissertations

The tension-tension fatigue behavior of a novel additively manufactured AM carbon fiber reinforced polymer matrix composite was studied. This novel material system consists of T1100 carbon fibers, and a UV photocured resin developed by Continuous Composites and Sartomer. Tensile properties and tension-tension fatigue were investigated for the 090 fiber orientation as well as for the ±45 fiber orientation. Specimens with 0/90 fiber orientation were tested at ambient laboratory temperature 23 °C and at elevated temperature 150 °C, while the specimens with the ±45 fiber orientation were tested only at ambient laboratory temperature. Tension-tension fatigue testing was carried out with a …

Mitigation Of The Laminar Separation Bubble Using Active Vortex Generators, Hayden Hitt

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

In-Situ Measurements Of Temperature And Emissivity During Msw Combustion Using Spectral Analysis And Multispectral Imaging Processing, Shu Zheng, Weiguang Cai, Ran Sui, Zixue Luo, Qiang Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

By using a novel multispectral imaging technology, the 2-D distributions of flame temperature and emissivity were measured in a 16 MW incinerator to co-fire municipal solid waste (MSW) and municipal sludge. A way to establish the relationship between the multispectral flame images and the temperature was proposed by combing the Newton iteration method and Hottel emissivity model. The results showed that the measured temperatures at different locations varied by 31.25% with a fixed steam evaporation rate, and 11.76% with different steam evaporation rates at a given port. The temperatures and emissivities decreased at upper locations due to the lower local …

Development Of A Trailing Edge Flap Using A Compliant Mechanism, Matthew Maybee

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Creation And Development Of An Obstacle Database For Uas Pathfinding, Cameron Clarke

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.