Frequency Response Modeling of Additive Friction Stir Deposition Parts with Print Defects

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dc.contributor.authorPennington, Brett Kennethen
dc.contributor.committeechairHuxtable, Scott T.en
dc.contributor.committeechairYu, Hangen
dc.contributor.committeememberLi, Zhengen
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2024-06-04T08:01:55Zen
dc.date.available2024-06-04T08:01:55Zen
dc.date.issued2024-06-03en
dc.description.abstractA change in a part's response to vibrations can be measured and utilized as a non-destructive testing method to detect deviations in the part's materials or geometry through processes such as laser acoustic resonance spectroscopy. This work focuses on leveraging vibration resonance to detect flaws in prints produced through additive friction stir deposition that arise through environmental contamination. More specifically, the use case considered is the printing of AA7075 in an iron oxide rich environment, where iron oxide dust or powder could accidentally be stirred into the printed material creating a print flaw. The modeling of printed parts contaminated with iron oxide to predict their natural frequencies is examined. Two different finite element models are discussed, which were created to represent contamination flaws with and without voids. The first model considers the case where a part is void-free. In this case, the model assumes a solid, homogeneous material condition in the stir region. The second model considers the case where voids are present in the part. This model leverages x-ray computed tomography data to build a representative mesh. These models show that with a well-understood part and corresponding flaw, it is possible to predict the natural frequencies of a flawed part. By leveraging the part vibration measurements and model predictions of known defects, it may be possible to gain insights into and characterize unknown print flaws.en
dc.description.abstractgeneralAn important aspect of product or part creation is checking consistency between parts. Methods that can verify a part is good without damaging the part are valuable, especially when only a few parts are being made, or there is a high chance of something going wrong. One way of checking a part is to shake it and watch how it reacts and bends. If there is a difference in how a part reacts to the shaking from a known good part, then there is a problem. This work examines creating computer simulations to predict how a part should react to shaking when it is good and how it should react when it has flaws. This work considers flaws caused by debris from the environment during part creation. This work also considers whether such debris causes holes or voids to form in the parts and conducts predictions with the holes included.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:40635en
dc.identifier.urihttps://hdl.handle.net/10919/119235en
dc.language.isoenen
dc.publisherVirginia Techen
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivatives 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/en
dc.subjectAdditive friction stir depositionen
dc.subjectfinite element analysisen
dc.subjectmodelingen
dc.subjectin-situ monitoringen
dc.subjectnon-destructive testingen
dc.subjectnatural frequencyen
dc.subjectfrequency modeen
dc.subjecteigenmode analysisen
dc.titleFrequency Response Modeling of Additive Friction Stir Deposition Parts with Print Defectsen
dc.typeThesisen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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