Matching Items (4)
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- All Subjects: Materials Science
- All Subjects: Supersonic
Description
A model has been developed to modify Euler-Bernoulli beam theory for wooden beams, using visible properties of wood knot-defects. Treating knots in a beam as a system of two ellipses that change the local bending stiffness has been shown to improve the fit of a theoretical beam displacement function to edge-line deflection data extracted from digital imagery of experimentally loaded beams. In addition, an Ellipse Logistic Model (ELM) has been proposed, using L1-regularized logistic regression, to predict the impact of a knot on the displacement of a beam. By classifying a knot as severely positive or negative, vs. mildly positive or negative, ELM can classify knots that lead to large changes to beam deflection, while not over-emphasizing knots that may not be a problem. Using ELM with a regression-fit Young's Modulus on three-point bending of Douglass Fir, it is possible estimate the effects a knot will have on the shape of the resulting displacement curve.
ContributorsSexton, Thurston Bryant (Author) / Takahashi, Timothy (Thesis director) / Jones, Donald (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2015-05
Description
This paper describes an aircraft design optimization tool for wave drag reduction. The tool synthesizes an aircraft wing and fuselage geometry using the Rhinoceros CAD program. It then implements an algorithm to perform area-ruling on the fuselage. The algorithm adjusts the cross-sectional area along the length of the fuselage, with the wing geometry fixed, to match a Sears-Haack distribution. Following the optimization of the area, the tool collects geometric data for analysis using legacy performance tools. This analysis revealed that performing the optimization yielded an average reduction in wave drag of 25% across a variety of Mach numbers on two different starting geometries. The goal of this project is to integrate this optimization tool into a larger trade study tool as it will allow for higher fidelity modeling as well as large improvements in transonic and supersonic drag performance.
ContributorsLeader, Robert William (Author) / Takahashi, Timothy (Thesis director) / Middleton, James (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The process of designing any real world blunt leading-edge wing is tedious andinvolves hundreds, if not thousands, of design iterations to narrow down a single design.
Add in the complexities of supersonic flow and the challenge increases exponentially.
One possible, and often common, pathway for this design is to jump straight into detailed
volume grid computational fluid dynamics (CFD), in which the physics of supersonic
flow are modeled directly but at a high computational cost and thus an incredibly long
design process. Classical aerodynamics experts have published work describing a process
which can be followed which might bypass the need for detailed CFD altogether.
This work outlines how successfully a simple vortex lattice panel method CFDcode can be used in the design process for a Mach 1.3 cruise speed airline wing concept.
Specifically, the success of the wing design is measured in its ability to operate subcritically (i.e. free of shock waves) even in a free stream flow which is faster than the
speed of sound. By using a modified version of Simple Sweep Theory, design goals are
described almost entirely based on defined critical pressure coefficients and critical Mach
numbers. The marks of a well-designed wing are discussed in depth and how these traits
will naturally lend themselves to a well-suited supersonic wing.
Unfortunately, inconsistencies with the published work are revealed by detailedCFD validation runs to be extensive and large in magnitude. These inconsistencies likely
have roots in several concepts related to supersonic compressible flow which are
explored in detail. The conclusion is made that the theory referenced in this work by the
classical aerodynamicists is incorrect and/or incomplete. The true explanation for the
perplexing shock wave phenomenon observed certainly lies in some convolution of the
factors discussed in this thesis. Much work can still be performed in the way of creating
an empirical model for shock wave formation across a highly swept wing with blunt
leading-edge airfoils.
Add in the complexities of supersonic flow and the challenge increases exponentially.
One possible, and often common, pathway for this design is to jump straight into detailed
volume grid computational fluid dynamics (CFD), in which the physics of supersonic
flow are modeled directly but at a high computational cost and thus an incredibly long
design process. Classical aerodynamics experts have published work describing a process
which can be followed which might bypass the need for detailed CFD altogether.
This work outlines how successfully a simple vortex lattice panel method CFDcode can be used in the design process for a Mach 1.3 cruise speed airline wing concept.
Specifically, the success of the wing design is measured in its ability to operate subcritically (i.e. free of shock waves) even in a free stream flow which is faster than the
speed of sound. By using a modified version of Simple Sweep Theory, design goals are
described almost entirely based on defined critical pressure coefficients and critical Mach
numbers. The marks of a well-designed wing are discussed in depth and how these traits
will naturally lend themselves to a well-suited supersonic wing.
Unfortunately, inconsistencies with the published work are revealed by detailedCFD validation runs to be extensive and large in magnitude. These inconsistencies likely
have roots in several concepts related to supersonic compressible flow which are
explored in detail. The conclusion is made that the theory referenced in this work by the
classical aerodynamicists is incorrect and/or incomplete. The true explanation for the
perplexing shock wave phenomenon observed certainly lies in some convolution of the
factors discussed in this thesis. Much work can still be performed in the way of creating
an empirical model for shock wave formation across a highly swept wing with blunt
leading-edge airfoils.
ContributorsKurus, Noah John (Author) / Takahashi, Timothy (Thesis advisor) / Benson, David (Committee member) / Niemczyk, Mary (Committee member) / Arizona State University (Publisher)
Created2020
Description
Automation has become a staple in high volume manufacturing, where the consistency and quality of a product carries as much importance as the quantity produced. The Aerospace Industry has a vested interest in expanding the application of automation beyond simply manufacturing. In this project, the process of systems engineering has been applied to the Conceptual Design Phase of product development; specifically, the Preliminary Structural Design of a Composite wing for an Unmanned Air Vehicle (UAV). Automated structural analysis can be used to develop a composite wing structure that can be directly rendered in Computer Aided Drafting (CAD) and validated using Finite Element Analysis (FEA). This concept provides the user with the ability to quickly iterate designs and demonstrates how different the “optimal light weight” composite structure must look for UAV systems of varied weight, range, and flight maneuverability.
ContributorsBlair, Martin Caceres (Author) / Takahashi, Timothy (Thesis advisor) / Murthy, Raghavendra (Committee member) / Perez, Ruben (Committee member) / Arizona State University (Publisher)
Created2021