Matching Items (22)
Filtering by
- All Subjects: Aerospace Engineering
- All Subjects: Structural Health Monitoring
- Creators: Takahashi, Timothy T
- Creators: Niemczyk, Mary
- Resource Type: Text
Description
This thesis encompasses research performed in the focus area of structural health monitoring. More specifically, this research focuses on high velocity impact testing of carbon fiber reinforced structures, especially plates, and evaluating the damage post-impact. To this end, various non-destructive evaluation techniques such as ultrasonic C-scan testing and flash thermography were utilized for post-impact analysis. MATLAB algorithms were written and refined for the localization and quantification of damage in plates using data from sensors such as piezoelectric and fiber Bragg gratings sensors. Throughout the thesis, the general plate theory and laminate plate theory, the operations and optimization of the gas gun, and the theory used for the damage localization algorithms will be discussed. Additional quantifiable results are to come in future semesters of experimentation, but this thesis outlines the framework upon which all the research will continue to advance.
ContributorsMccrea, John Patrick (Author) / Chattopadhyay, Aditi (Thesis director) / Borkowski, Luke (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Department of Military Science (Contributor)
Created2015-05
Description
This thesis encompasses research performed in the focus area of structural health monitoring. More specifically, this research focuses on high velocity impact testing of carbon fiber reinforced structures, especially plates, and evaluating the damage post-impact. To this end, various non-destructive evaluation techniques such as ultrasonic C-scan testing and flash thermography were utilized for post-impact analysis. MATLAB algorithms were written and refined for the localization and quantification of damage in plates using data from sensors such as piezoelectric and fiber Bragg gratings sensors. Throughout the thesis, the general plate theory and laminate plate theory, the operations and optimization of the gas gun, and the theory used for the damage localization algorithms will be discussed. Additional quantifiable results are to come in future semesters of experimentation, but this thesis outlines the framework upon which all the research will continue to advance.
ContributorsMccrea, John Patrick (Author) / Chattopadhyay, Aditi (Thesis director) / Borkowski, Luke (Committee member) / Department of Military Science (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This work uses Arizona State University’s (ASU) newly developed high-speed vehicle stability and control screening methodologies to reverse-engineer famous United States Air Force (USAF) flight tests from the 1950s and 1960s. This thesis analyzes the root cause of Chuck Yeager's fateful 1953 supersonic spin in the Bell X-1A to become the "Fastest Man Alive". This thesis then takes a look back at Neil Armstrong's inadvertent atmospheric skip in the North American X-15 and his subsequent hypersonic flight months later. The fundamental flying qualities assessment shown in this work begins with calculating rigid-body frequencies and damping ratios of an aircraft to Military Standard (MIL) requirements, and uses these to create a full, classical stability and control analysis of a high-speed vehicle. Through reverse engineering the flight envelopes and missions for the above aircraft, it appears that the near-disasters of each flight were due to a confluence of then overlooked, yet fundamental, aerodynamic instabilities.
ContributorsLorenzo, Will (Author) / Takahashi, Timothy T (Thesis advisor) / Dahm, Werner J.A. (Committee member) / Grandhi, Ramana V (Committee member) / Arizona State University (Publisher)
Created2023
Description
Formula 1 car front wings have evolved significantly over the last fifty years. Looking back at the past decade shows significant changes made due to rules and regulations by the Federation Internationale de l'Automobile and an increased understanding of aerodynamic concepts. There seems to be a trend where aerodynamic design concepts, previously seen in aviation, are being applied to Formula 1 front wings; this helps race teams increase downforce and reduce drag. This thesis analyzes these changes made over the past years and relates the material back to material that was learned by the aviation industry and attempts to synthesize conceptual Formula 1 front Wing designs using VORLAX, a vortex lattice panel method, used in the aviation industry. This insight would be beneficial for Formula 1 teams as there are budget and time restrictions applied to Computational Fluid Dynamic and wind tunnel testing, but panel methods are run in a matter of seconds as opposed to hours or days. So, if verified, preliminary designs can be rapidly tested to optimize the workflow and reduce the time required for Computational Fluid Dynamic and wind tunnel testing.
ContributorsRatnayake, Sajana Sathsara (Author) / Takahashi, Timothy T (Thesis advisor) / Perez, Ruben E (Committee member) / Kim, Jeonglae (Committee member) / Arizona State University (Publisher)
Created2023
Description
Advanced fibrous composite materials exhibit outstanding thermomechanical performance under extreme environments, which make them ideal for structural components that are used in a wide range of aerospace, nuclear, and defense applications. The integrity and residual useful life of these components, however, are strongly influenced by their inherent material flaws and defects resulting from the complex fabrication processes. These defects exist across multiple length scales and govern several scale-dependent inelastic deformation mechanisms of each of the constituents as well as their composite damage anisotropy. Tailoring structural components for optimal performance requires addressing the knowledge gap regarding the microstructural material morphology that governs the structural scale damage and failure response. Therefore, there is a need for a high-fidelity multiscale modeling framework and scale-specific in-situ experimental characterization that can capture complex inelastic mechanisms, including damage initiation and propagation across multiple length scales. This dissertation presents a novel multiscale computational framework that accounts for experimental information pertinent to microstructure morphology and architectural variabilities to investigate the response of ceramic matrix composites (CMCs) with manufacturing-induced defects. First, a three-dimensional orthotropic viscoplasticity creep formulation is developed to capture the complex temperature- and time-dependent constituent load transfer mechanisms in different CMC material systems. The framework also accounts for a reformulated fracture mechanics-informed matrix damage model and the Curtin progressive fiber damage model to capture the complex scale-dependent damage and failure mechanisms through crack kinetics and porosity growth. Next, in-situ experiments using digital image correlation (DIC) are performed to capture the damage and failure mechanisms in CMCs and to validate the high-fidelity modeling results.
The dissertation also presents an exhaustive experimental investigation into the effects of temperature and manufacturing-induced defects on toughened epoxy adhesives and hybrid composite-metallic bonded joints. Nondestructive evaluation techniques are utilized to characterize the inherent defects morphology of the bulk adhesives and bonded interface. This is followed by quasi-static tensile tests conducted at extreme hot and cold temperature conditions. The damage mechanisms and failure modes are investigated using in-situ DIC and a high-resolution camera. The information from the morphology characterization studies is used to reconstruct high-fidelity geometries of the test specimens for finite element analysis.
ContributorsKhafagy, Khaled Hassan Abdo (Author) / Chattopadhyay, Aditi (Thesis advisor) / Fard, Masoud Y. (Committee member) / Milcarek, Ryan (Committee member) / Stoumbos, Tom (Committee member) / Borkowski, Luke (Committee member) / Arizona State University (Publisher)
Created2022
Description
This thesis describes key Stability & Control parameters and a methodology for screening aircraft configurations for adequate handling qualities. For screening aircraft, a general-purpose Excel/ Visual Basic for Application (VBA) analysis tool was built. The analysis tool has built-in functionality to analyze aircraft utilizing a rudder for primary yaw control, collective horizontal tail for pitch, and either aileron or differential horizontal tail for roll control. Additionally, the tool transforms aerodynamic coefficients from the moment reference point to various center of gravity locations while saving data in Stability Axis and Body Axis; it also implements pitch trim. Key stability parameters of interest are the Short Period and Dutch Roll Frequencies, Roll and Spiral time constants, Cnβdynamic, Lateral Control Departure Parameter (LCDP), as well as the stick-fixed Short Period and Dutch Roll Damping. Other areas of interest include pitch and lateral-directional trim as well as the implementation of an Aileron-Rudder Interconnect system. This thesis uses the tool to analyze two historical: 1) the Bell X-2 and 2) the North American X-15 and two theoretical: 3) the “Sky Cruiser” and 4) the generic High-Speed Slender Aircraft (HSSA), aircraft. This thesis identifies varying Stability & Control problems between these aircraft and allows one to explore potential solutions to remedy their inherent flaws.
ContributorsO'Brien, Kevin Patrick (Author) / Takahashi, Timothy T (Thesis advisor) / Dahm, Werner J (Committee member) / Cotting, Christopher M (Committee member) / Arizona State University (Publisher)
Created2023
Description
Two methods of improving the life and efficiency of the Pulsed Inductive Thruster
(PIT) have been investigated. The first is a trade study of available switches to
determine the best device to implement in the PIT design. The second is the design
of a coil to improve coupling between the accelerator coil and the plasma. Experiments
were done with both permanent and electromagnets to investigate the feasibility of
implementing a modified Halbach array within the PIT to promote better plasma
coupling and decrease the unused space within the thruster. This array proved to
promote more complete coupling on the edges of the coil where it had been weak in
previous studies. Numerical analysis was done to predict the performance of a PIT
that utilized each suggested switch type. This model utilized the Alfven velocity to
determine the critical mass and energy of these theoretical thrusters.
(PIT) have been investigated. The first is a trade study of available switches to
determine the best device to implement in the PIT design. The second is the design
of a coil to improve coupling between the accelerator coil and the plasma. Experiments
were done with both permanent and electromagnets to investigate the feasibility of
implementing a modified Halbach array within the PIT to promote better plasma
coupling and decrease the unused space within the thruster. This array proved to
promote more complete coupling on the edges of the coil where it had been weak in
previous studies. Numerical analysis was done to predict the performance of a PIT
that utilized each suggested switch type. This model utilized the Alfven velocity to
determine the critical mass and energy of these theoretical thrusters.
ContributorsRaines, Taylor (Author) / Takahashi, Timothy T (Thesis advisor) / White, Daniel B (Committee member) / Dahm, Werner (Committee member) / Arizona State University (Publisher)
Created2018
Description
This paper describes an effort to bring wing structural stiffness and aeroelastic considerations early in the conceptual design process with an automated tool. Stiffness and aeroelasticity can be well represented with a stochastic model during conceptual design because of the high level of uncertainty and variability in wing non-structural mass such as fuel loading and control surfaces. To accomplish this, an improvement is made to existing design tools utilizing rule based automated design to generate wing torque box geometry from a specific wing outer mold-line. Simple analysis on deflection and inferred stiffness shows how early conceptual design choices can strongly impact the stiffness of the structure. The impacts of design choices and how the buckling constraints drive structural weight in particular examples are discussed. The model is then carried further to include a finite element model (FEM) to analyze resulting mode shapes and frequencies for use in aeroelastic analysis. The natural frequencies of several selected wing torque boxes across a range of loading cases are compared.
ContributorsMiskin, Daniel L (Author) / Takahashi, Timothy T (Thesis advisor) / Mignolet, Marc (Committee member) / Murthy, Raghavendra (Committee member) / Arizona State University (Publisher)
Created2018
Description
Modern aircraft are expected to fly faster and more efficiently than their predecessors. To improve aerodynamic efficiency, designers must carefully consider and handle shock wave formation. Presently, many designers utilize computationally heavy optimization methods to design wings. While these methods may work, they do not provide insight. This thesis aims to better understand fundamental methods that govern wing design. In order to further understand the flow in the transonic regime, this work revisits the Transonic Similarity Rule. This rule postulates an equivalent incompressible geometry to any high speed geometry in flight and postulates a “stretching” analogy. This thesis utilizes panel methods and Computational Fluid Dynamics (CFD) to show that the “stretching” analogy is incorrect, but instead the flow is transformed by a nonlinear “scaling” of the flow velocity. This work also presents data to show the discrepancies between many famous authors in deriving the accurate Critical Pressure Coefficient (Cp*) equation for both swept and unswept wing sections. The final work of the thesis aims to identify the correct predictive methods for the Critical Pressure Coefficient.
ContributorsKirkman, Jeffrey J (Author) / Takahashi, Timothy T (Thesis advisor) / Wells, Valana (Committee member) / Herman, Marcus (Committee member) / Arizona State University (Publisher)
Created2016
Description
There are significant fuel consumption consequences for non-optimal flight operations. This study is intended to analyze and highlight areas of interest that affect fuel consumption in typical flight operations. By gathering information from actual flight operators (pilots, dispatch, performance engineers, and air traffic controllers), real performance issues can be addressed and analyzed. A series of interviews were performed with various individuals in the industry and organizations. The wide range of insight directed this study to focus on FAA regulations, airline policy, the ATC system, weather, and flight planning. The goal is to highlight where operational performance differs from design intent in order to better connect optimization with actual flight operations. After further investigation and consensus from the experienced participants, the FAA regulations do not need any serious attention until newer technologies and capabilities are implemented. The ATC system is severely out of date and is one of the largest limiting factors in current flight operations. Although participants are pessimistic about its timely implementation, the FAA's NextGen program for a future National Airspace System should help improve the efficiency of flight operations. This includes situational awareness, weather monitoring, communication, information management, optimized routing, and cleaner flight profiles like Required Navigation Performance (RNP) and Continuous Descent Approach (CDA). Working off the interview results, trade-studies were performed using an in-house flight profile simulation of a Boeing 737-300, integrating NASA legacy codes EDET and NPSS with a custom written mission performance and point-performance "Skymap" calculator. From these trade-studies, it was found that certain flight conditions affect flight operations more than others. With weather, traffic, and unforeseeable risks, flight planning is still limited by its high level of precaution. From this study, it is recommended that air carriers increase focus on defining policies like load scheduling, CG management, reduction in zero fuel weight, inclusion of performance measurement systems, and adapting to the regulations to best optimize the spirit of the requirement.. As well, air carriers should create a larger drive to implement the FAA's NextGen system and move the industry into the future.
ContributorsHeitzman, Nicholas (Author) / Takahashi, Timothy T (Thesis advisor) / Wells, Valana (Thesis advisor) / Feigh, Karen (Committee member) / Arizona State University (Publisher)
Created2014