Size effects in out-of-plane bending in elastic honeycombs fabricated using additive manufacturing : modeling and experimental results
| dc.contributor.advisor | Kovar, Desiderio | en |
| dc.contributor.committeeMember | Taleff, Eric M. | en |
| dc.contributor.committeeMember | Rodin, Gregory J. | en |
| dc.contributor.committeeMember | Bourell, David L. | en |
| dc.contributor.committeeMember | Haberman, Michael R. | en |
| dc.creator | Mikulak, James Kevin | en |
| dc.date.accessioned | 2012-02-06T21:31:48Z | en |
| dc.date.available | 2012-02-06T21:31:48Z | en |
| dc.date.issued | 2011-12 | en |
| dc.date.submitted | December 2011 | en |
| dc.date.updated | 2012-02-06T21:32:06Z | en |
| dc.description | text | en |
| dc.description.abstract | Size effects in out-of-plane bending stiffness of honeycomb cellular materials were studied using analytical mechanics of solids modeling, fabrication of samples and mechanical testing. Analysis predicts a positive size-effect relative to continuum model predictions in the flexure stiffness of a honeycombed beam loaded in out-of-plane bending. A method of determining the magnitude of that effect for several different methods of constructing or assembling square-celled and hexagonal-celled materials, using both single-walled and doubled-walled construction methods is presented. Hexagonal and square-celled honeycombs, with varying volume fractions were fabricated in Nylon 12 using Selective Laser Sintering. The samples were mechanically tested in three-point and four point-bending to measure flexure stiffness. The results from standard three-point flexure tests, did not agree with predictions based on a mechanics of solids model for either square or hexagonal-celled samples. Results for four-point bending agreed with the mechanics of solids model for the square-celled geometries but not for the hexagonal-celled geometries. A closed form solution of an elasticity model for the response of the four-point bending configuration was developed, which allows interpretation of recorded displacement data at two points and allows separation the elastic bending from the localized, elastic/plastic deformation that occurs between the loading rollers and the specimen’s surface. This localized deformation was significant in the materials tested. With this analysis, the four-point bending data agreed well with the mechanics of solids predictions. | en |
| dc.description.department | Materials Science and Engineering | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.slug | 2152/ETD-UT-2011-12-4565 | en |
| dc.identifier.uri | http://hdl.handle.net/2152/ETD-UT-2011-12-4565 | en |
| dc.language.iso | eng | en |
| dc.subject | Size effects | en |
| dc.subject | Out-of-plane bending | en |
| dc.subject | Elastic bending | en |
| dc.subject | Additive manufacturing | en |
| dc.subject | Selective laser sintering | en |
| dc.subject | Honeycombs | en |
| dc.subject | Mechanics of solids | en |
| dc.subject | Nylon 12 | en |
| dc.subject | PA12 | en |
| dc.subject | Bending stiffness | en |
| dc.subject | Mechanical testing | en |
| dc.subject | Cellular solids | en |
| dc.subject | Cellular foams | en |
| dc.subject | Foams | en |
| dc.subject | Square-celled honeycombs | en |
| dc.subject | Hexagonal-celled honeycombs | en |
| dc.subject | Elasticity | en |
| dc.title | Size effects in out-of-plane bending in elastic honeycombs fabricated using additive manufacturing : modeling and experimental results | en |
| dc.type.genre | thesis | en |
| thesis.degree.department | Materials Science and Engineering | en |
| thesis.degree.discipline | Materials Science and Engineering | en |
| thesis.degree.grantor | University of Texas at Austin | en |
| thesis.degree.level | Doctoral | en |
| thesis.degree.name | Doctor of Philosophy | en |