{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/45361"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/45361","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Variable complexity modeling of postbuckled stiffeners for delamination initiation","abstract":"Delamination at the free edge is analyzed as a mode of failure for uniaxial compression of postbuckled structural components. Analyses are performed for I-section stiffeners and for a dropped-ply laminate, all of which failed due to free edge delamination in earlier experimental studies. These specimens were made of AS4/3502 graphite-epoxy unidirectional tape. The nonlinear response of the specimens is modeled by a geometrically nonlinear finite element analysis. A variable-complexity modeling scheme is developed to economize computer resources for the nonlinear analysis. The three-dimensional stress field near the free edge is investigated by employing 20-node solid elements in that region. A dimensionless delamination index is calculated to investigate the severity of the interlaminar stress state. Numerical results correlated reasonably well with the experiments on load-end shortening plots. The nodallines and/or inflection points of the out-of-plane deflection along the free edge in the postbuckled configuration are found to be delamination critical sites. Both interlaminar shear stress tangent to the free edge and tensile interlaminar normal stress are significant at these critical locations and are likely to initiate delamination.","abstract_html":"Delamination at the free edge is analyzed as a mode of failure for uniaxial compression of postbuckled structural components. Analyses are performed for I-section stiffeners and for a dropped-ply laminate, all of which failed due to free edge delamination in earlier experimental studies. These specimens were made of AS4/3502 graphite-epoxy unidirectional tape. The nonlinear response of the specimens is modeled by a geometrically nonlinear finite element analysis. A variable-complexity modeling scheme is developed to economize computer resources for the nonlinear analysis. The three-dimensional stress field near the free edge is investigated by employing 20-node solid elements in that region. A dimensionless delamination index is calculated to investigate the severity of the interlaminar stress state. Numerical results correlated reasonably well with the experiments on load-end shortening plots. The nodallines and/or inflection points of the out-of-plane deflection along the free edge in the postbuckled configuration are found to be delamination critical sites. Both interlaminar shear stress tangent to the free edge and tensile interlaminar normal stress are significant at these critical locations and are likely to initiate delamination.","abstract_has_math":false,"creators":["Barlas, Fatma Aylin"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Aerospace Engineering","degree_department":"Aerospace Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Johnson, Eric R."],"committee_members":["Gürdal, Zafer","Kapania, Rakesh K."],"year":1993,"date_issued":"1993-06-18","date_published":"1993-06-18","updated_at":"2026-07-22T22:20:16Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-10312009-020245"],"render_values":[{"text":"etd-10312009-020245","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/45361","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Johnson, Eric R."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Gürdal, Zafer","Kapania, Rakesh K."]},{"key":"dc:contributor.department","label":"Department","values":["Aerospace Engineering"]},{"key":"dc:creator","label":"Author","values":["Barlas, Fatma Aylin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T21:48:29Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T21:48:29Z","2009-10-31"]},{"key":"dc:date.issued","label":"Date","values":["1993-06-18"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-10312009-020245"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/45361"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Delamination at the free edge is analyzed as a mode of failure for uniaxial compression of postbuckled structural components. Analyses are performed for I-section stiffeners and for a dropped-ply laminate, all of which failed due to free edge delamination in earlier experimental studies. These specimens were made of AS4/3502 graphite-epoxy unidirectional tape. The nonlinear response of the specimens is modeled by a geometrically nonlinear finite element analysis. A variable-complexity modeling scheme is developed to economize computer resources for the nonlinear analysis. The three-dimensional stress field near the free edge is investigated by employing 20-node solid elements in that region. A dimensionless delamination index is calculated to investigate the severity of the interlaminar stress state. Numerical results correlated reasonably well with the experiments on load-end shortening plots. The nodallines and/or inflection points of the out-of-plane deflection along the free edge in the postbuckled configuration are found to be delamination critical sites. Both interlaminar shear stress tangent to the free edge and tensile interlaminar normal stress are significant at these critical locations and are likely to initiate delamination."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["BTD"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Variable complexity modeling of postbuckled stiffeners for delamination initiation"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Johnson, Eric R."],"dc:contributor.committeemember":["Gürdal, Zafer","Kapania, Rakesh K."],"dc:contributor.department":["Aerospace Engineering"],"dc:creator":["Barlas, Fatma Aylin"],"dc:date.accessioned":["2014-03-14T21:48:29Z"],"dc:date.available":["2014-03-14T21:48:29Z","2009-10-31"],"dc:date.issued":["1993-06-18"],"dc:description.abstract":["Delamination at the free edge is analyzed as a mode of failure for uniaxial compression of postbuckled structural components. 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Both interlaminar shear stress tangent to the free edge and tensile interlaminar normal stress are significant at these critical locations and are likely to initiate delamination."],"dc:description.degree":["Master of Science"],"dc:format.medium":["BTD"],"dc:format.mimetype":["application/pdf"],"dc:identifier.other":["etd-10312009-020245"],"dc:identifier.uri":["http://hdl.handle.net/10919/45361"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Variable complexity modeling of postbuckled stiffeners for delamination initiation"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:16Z"}