{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/33982"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/33982","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Fatigue Life of Hybrid FRP Composite Beams","abstract":"As fiber reinforced polymer (FRP) structures find application in highway bridge structures, methodologies for describing their long-term performance under service loading will be a necessity for designers. The designer of FRP bridge structures is faced with out-of-plane damage and delamination at ply interfaces. The damage most often occurs between hybrid plys and dominates the life time response of a thick section FRP structure. The focus of this work is on the performance of the 20.3 cm (8 in) pultruded, hybrid double web I-beam structural shape. Experimental four-point bend fatigue results indicate that overall stiffness reduction of the structure is controlled by the degradation of the tensile flange. The loss of stiffness in the tensile flange results in the redistribution of the stresses and strains, until the initiation of failure by delamination in the compression flange. These observations become the basis of the assumptions used to develop an analytical life prediction model. In the model, the tensile flange stiffness is reduced based on coupon test data, and is used to determine the overall strength reduction of the beam in accordance the residual strength life prediction methodology. Delamination initiation is based on the out-of-plane stress sz at the free edge. The stresses are calculated using two different approximations, the Primitive Delamination Model and the Minimization of Complementary Energy. The model successfully describes the onset of delamination prior to fiber failure and suggests that out-of-plane failure controls the life of the structure.","abstract_html":"As fiber reinforced polymer (FRP) structures find application in highway bridge structures, methodologies for describing their long-term performance under service loading will be a necessity for designers. The designer of FRP bridge structures is faced with out-of-plane damage and delamination at ply interfaces. The damage most often occurs between hybrid plys and dominates the life time response of a thick section FRP structure. The focus of this work is on the performance of the 20.3 cm (8 in) pultruded, hybrid double web I-beam structural shape. Experimental four-point bend fatigue results indicate that overall stiffness reduction of the structure is controlled by the degradation of the tensile flange. The loss of stiffness in the tensile flange results in the redistribution of the stresses and strains, until the initiation of failure by delamination in the compression flange. These observations become the basis of the assumptions used to develop an analytical life prediction model. In the model, the tensile flange stiffness is reduced based on coupon test data, and is used to determine the overall strength reduction of the beam in accordance the residual strength life prediction methodology. Delamination initiation is based on the out-of-plane stress sz at the free edge. The stresses are calculated using two different approximations, the Primitive Delamination Model and the Minimization of Complementary Energy. The model successfully describes the onset of delamination prior to fiber failure and suggests that out-of-plane failure controls the life of the structure.","abstract_has_math":false,"creators":["Senne, Jolyn Louise"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Engineering Mechanics","degree_department":"Engineering Mechanics","school":null,"contributors":[],"advisors":[],"committee_chairs":["Lesko, John J."],"committee_members":["Cousins, Thomas E.","Case, Scott W."],"year":2000,"date_issued":"2000-07-10","date_published":"2000-07-10","updated_at":"2026-07-22T22:19:41Z","subjects":["pultruded composites","hybrid composites","fiber-reinforced polymer (FRP) composites","life prediction","Fatigue","infrastructure"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-07132000-14530012"],"render_values":[{"text":"etd-07132000-14530012","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/33982","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Lesko, John J."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Cousins, Thomas E.","Case, Scott W."]},{"key":"dc:contributor.department","label":"Department","values":["Engineering Mechanics"]},{"key":"dc:creator","label":"Author","values":["Senne, Jolyn Louise"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:41:22Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:41:22Z","2001-07-17"]},{"key":"dc:date.issued","label":"Date","values":["2000-07-10"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Engineering Mechanics"]},{"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":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["pultruded composites","hybrid composites","fiber-reinforced polymer (FRP) composites","life prediction","Fatigue","infrastructure"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"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-07132000-14530012"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/33982"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["As fiber reinforced polymer (FRP) structures find application in highway bridge structures, methodologies for describing their long-term performance under service loading will be a necessity for designers. The designer of FRP bridge structures is faced with out-of-plane damage and delamination at ply interfaces. The damage most often occurs between hybrid plys and dominates the life time response of a thick section FRP structure. The focus of this work is on the performance of the 20.3 cm (8 in) pultruded, hybrid double web I-beam structural shape. Experimental four-point bend fatigue results indicate that overall stiffness reduction of the structure is controlled by the degradation of the tensile flange. The loss of stiffness in the tensile flange results in the redistribution of the stresses and strains, until the initiation of failure by delamination in the compression flange. These observations become the basis of the assumptions used to develop an analytical life prediction model. In the model, the tensile flange stiffness is reduced based on coupon test data, and is used to determine the overall strength reduction of the beam in accordance the residual strength life prediction methodology. Delamination initiation is based on the out-of-plane stress sz at the free edge. The stresses are calculated using two different approximations, the Primitive Delamination Model and the Minimization of Complementary Energy. The model successfully describes the onset of delamination prior to fiber failure and suggests that out-of-plane failure controls the life of the structure."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Fatigue Life of Hybrid FRP Composite Beams"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Lesko, John J."],"dc:contributor.committeemember":["Cousins, Thomas E.","Case, Scott W."],"dc:contributor.department":["Engineering Mechanics"],"dc:creator":["Senne, Jolyn Louise"],"dc:date.accessioned":["2014-03-14T20:41:22Z"],"dc:date.available":["2014-03-14T20:41:22Z","2001-07-17"],"dc:date.issued":["2000-07-10"],"dc:description.abstract":["As fiber reinforced polymer (FRP) structures find application in highway bridge structures, methodologies for describing their long-term performance under service loading will be a necessity for designers. The designer of FRP bridge structures is faced with out-of-plane damage and delamination at ply interfaces. The damage most often occurs between hybrid plys and dominates the life time response of a thick section FRP structure. The focus of this work is on the performance of the 20.3 cm (8 in) pultruded, hybrid double web I-beam structural shape. Experimental four-point bend fatigue results indicate that overall stiffness reduction of the structure is controlled by the degradation of the tensile flange. The loss of stiffness in the tensile flange results in the redistribution of the stresses and strains, until the initiation of failure by delamination in the compression flange. These observations become the basis of the assumptions used to develop an analytical life prediction model. In the model, the tensile flange stiffness is reduced based on coupon test data, and is used to determine the overall strength reduction of the beam in accordance the residual strength life prediction methodology. Delamination initiation is based on the out-of-plane stress sz at the free edge. The stresses are calculated using two different approximations, the Primitive Delamination Model and the Minimization of Complementary Energy. 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