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dc.contributor.advisorLamberson, Leslie
dc.contributor.authorBrunstad, Nicholas John
dc.date.accessioned2021-06-28T10:13:39Z
dc.date.accessioned2022-02-03T13:24:30Z
dc.date.available2021-06-28T10:13:39Z
dc.date.available2022-02-03T13:24:30Z
dc.date.issued2021
dc.identifierBrunstad_mines_0052N_12122.pdf
dc.identifierT 9090
dc.identifier.urihttps://hdl.handle.net/11124/176403
dc.descriptionIncludes bibliographical references.
dc.description2021 Spring.
dc.description.abstractThis work examines the fracture behavior of additively manufactured (AM) thermosetting resins to enable rapid production of lightweight and functional polymeric and composite materials that can meet a wide range of applications. Specifically, the role of print orientation on the quasi-static and dynamic fracture response of two distinct AM polymer materials, DA-3 and PM-EM828, is presented. While predictive simulations often leverage quasi-static fracture criterion, impulsively loaded cracks can have substantially different resistance to growth. To study dynamic fracture, a unique long-bar apparatus is used to fire a striker at the opposite end of notched and pre-cracked specimens to create a dominantly dynamic Mode-I (opening) load. Digital Image Correlation (DIC) is used in conjunction with ultra-high-speed imaging to capture the evolving displacement fields ahead of the crack tip. The elastodynamic solution for a stationary crack is optimized using a least square fit to extract the evolving critical stress intensity factor (SIF) leading to fracture initiation. These results are compared to quasi-static experiments of the same material and similar geometries on a standard load frame. Findings suggest that the print orientation does slightly affect the quasi-static and dynamic fracture response of DA-3, however the PM-EM828 does not show statistically significant orientation dependencies on fracture behavior. The DA-3 exhibited between 46% to 60% higher quasi-static fracture toughness values than dynamic, on average, but the trends mirrored the printed orientation dependency of dynamic loading. Conversely, PM-EM828 exhibited approximately 20% lower quasi-static fracture values than dynamic values and had little to no orientation dependency. The overall toughness of the PM-EM828 layers are on a similar level to their interlayer adhesion zones, suggesting why there may be little print orientation dependence. Conversely, the DA-3 layers are less brittle than their interlayer adhesion zones, and so the orientation of the adhesion zones with respect to the print orientation seems to allow for a greater resistance to fracture.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2021 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectdigital light processing
dc.subjectfracture mechanics
dc.subjectquasi-static fracture
dc.subjectdynamic fracture
dc.subjectadditive manufacturing
dc.subjectprint orientation
dc.titleStudy of layer orientation on the fracture behavior of two additively manufactured thermoset resins, A
dc.typeText
dc.contributor.committeememberBerger, John R.
dc.contributor.committeememberEliasson, Veronica
dc.contributor.committeememberKoumlis, Stylianos
thesis.degree.nameMaster of Science (M.S.)
thesis.degree.levelMasters
thesis.degree.disciplineMechanical Engineering
thesis.degree.grantorColorado School of Mines


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