MODULATED THERMOGRAPHIC ANALYSIS OF THERMAL DIFFUSIVITY IN MATERIALS USING EULERIAN VIDEO MAGNIFICATION
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Authors
Freschi, Gianluca C.
Subjects
EVM
additive manufacturing
IRT
FLIR
thermography
Eulerian video magnification
3D printing
thermal diffusivity
conduction
imaging systems
Angstrom method
MATLAB
additive manufacturing
IRT
FLIR
thermography
Eulerian video magnification
3D printing
thermal diffusivity
conduction
imaging systems
Angstrom method
MATLAB
Advisors
Gunduz, Ibrahim E.
Date of Issue
2024-06
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
Additive manufacturing systems require in-situ diagnostics to identify defects during builds to properly assess final part properties. However, many defects that originate are sub-surface between newly built layers, which requires x-rays or other cumbersome methods to detect them. Infrared thermography (IRT) is a method that is used to detect the thermal signature of heat flux through an analyzed sample. Although it is a useful technique, depending on the part and heat source employed, the thermal response can be very faint and difficult for typical infrared (IR) detectors to detect and record. Eulerian video magnification (EVM) is an optical amplification technique capable of revealing and displaying periodic temporal and spatial variations in videos that are below the sensitivity of imaging systems. EVM can be used in IR videos to show phenomena occurring at temporal frequencies selected by the user. This work investigates different geometries of periodically heated polymer and metal parts and the optical amplification of temperature gradients to determine their thermal diffusivity via MATLAB based application of the Angstrom Method. This type of imaging can also be employed to reveal layer adhesion flaws well below a surface, thus potentially allowing for a non-destructive visualization of the print quality of metal components or structures.
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Thesis
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Distribution Statement
Distribution Statement A. Approved for public release: Distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.