{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/113503"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/113503","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Damage location and estimation in large space structures","abstract":"This thesis presents a unique method of damage detection in large space structures. The goal is to develop an efficient algorithm which can be automated in an on-line format, and can asses damage in many elements. Theses are goals not realized by current methods. Damage incurred in a structural member is modeled as a linear reduction in that member's modulus of elasticity. The damaged structure's global stiffness matrix is expressed as the healthy global stiffness matrix minus some perturbation matrix. A vector expression of the perturbation matrix allows the percent reduction in damage to be solved for exactly in an equation involving the healthy truss model and a mode identified from the damaged structure. An algorithm for locating and estimating single-element damage is built around this equation. Simulations of the algorithm are performed on two planar truss models. The vector expression of the damage perturbation is shown to lead to a mode shape - strain energy relationship. From this, it is shown that a smaller truss model can be computed from element stiffness vectors. Damage can then be detected as existing among a small group of elements. Simulations show detection in one group to be independent from damage in other groups. From this information, a dimensionally expanded version of the single-element detection method can be used to exactly locate and estimate damage in many elements simultaneously. This process is presented as a sequential algorithm which meets all of the desired criteria.","abstract_html":"This thesis presents a unique method of damage detection in large space structures. The goal is to develop an efficient algorithm which can be automated in an on-line format, and can asses damage in many elements. Theses are goals not realized by current methods. Damage incurred in a structural member is modeled as a linear reduction in that member's modulus of elasticity. The damaged structure's global stiffness matrix is expressed as the healthy global stiffness matrix minus some perturbation matrix. A vector expression of the perturbation matrix allows the percent reduction in damage to be solved for exactly in an equation involving the healthy truss model and a mode identified from the damaged structure. An algorithm for locating and estimating single-element damage is built around this equation. Simulations of the algorithm are performed on two planar truss models. The vector expression of the damage perturbation is shown to lead to a mode shape - strain energy relationship. From this, it is shown that a smaller truss model can be computed from element stiffness vectors. Damage can then be detected as existing among a small group of elements. Simulations show detection in one group to be independent from damage in other groups. From this information, a dimensionally expanded version of the single-element detection method can be used to exactly locate and estimate damage in many elements simultaneously. This process is presented as a sequential algorithm which meets all of the desired criteria.","abstract_has_math":false,"creators":["Twitty, Gregory B."],"institution":"Virginia Polytechnic Institute and State University","degree_name":"M.S.","degree_level":"masters","degree_discipline":"Electrical Engineering","degree_department":"Electrical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1993,"date_issued":"1993","date_published":"1993","updated_at":"2026-07-22T22:20:34Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/113503","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Electrical Engineering"]},{"key":"dc:creator","label":"Author","values":["Twitty, Gregory B."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-01-27T04:47:49Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-01-27T04:47:49Z"]},{"key":"dc:date.issued","label":"Date","values":["1993"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"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":["Electrical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"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.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/113503"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis presents a unique method of damage detection in large space structures. The goal is to develop an efficient algorithm which can be automated in an on-line format, and can asses damage in many elements. Theses are goals not realized by current methods. Damage incurred in a structural member is modeled as a linear reduction in that member's modulus of elasticity. The damaged structure's global stiffness matrix is expressed as the healthy global stiffness matrix minus some perturbation matrix. A vector expression of the perturbation matrix allows the percent reduction in damage to be solved for exactly in an equation involving the healthy truss model and a mode identified from the damaged structure. An algorithm for locating and estimating single-element damage is built around this equation. Simulations of the algorithm are performed on two planar truss models. The vector expression of the damage perturbation is shown to lead to a mode shape - strain energy relationship. From this, it is shown that a smaller truss model can be computed from element stiffness vectors. Damage can then be detected as existing among a small group of elements. Simulations show detection in one group to be independent from damage in other groups. From this information, a dimensionally expanded version of the single-element detection method can be used to exactly locate and estimate damage in many elements simultaneously. This process is presented as a sequential algorithm which meets all of the desired criteria."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["M.S."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Damage location and estimation in large space structures"]}]}],"canonical_facts":{"dc:contributor.department":["Electrical Engineering"],"dc:creator":["Twitty, Gregory B."],"dc:date.accessioned":["2023-01-27T04:47:49Z"],"dc:date.available":["2023-01-27T04:47:49Z"],"dc:date.issued":["1993"],"dc:description.abstract":["This thesis presents a unique method of damage detection in large space structures. The goal is to develop an efficient algorithm which can be automated in an on-line format, and can asses damage in many elements. Theses are goals not realized by current methods. Damage incurred in a structural member is modeled as a linear reduction in that member's modulus of elasticity. The damaged structure's global stiffness matrix is expressed as the healthy global stiffness matrix minus some perturbation matrix. A vector expression of the perturbation matrix allows the percent reduction in damage to be solved for exactly in an equation involving the healthy truss model and a mode identified from the damaged structure. An algorithm for locating and estimating single-element damage is built around this equation. Simulations of the algorithm are performed on two planar truss models. The vector expression of the damage perturbation is shown to lead to a mode shape - strain energy relationship. From this, it is shown that a smaller truss model can be computed from element stiffness vectors. Damage can then be detected as existing among a small group of elements. Simulations show detection in one group to be independent from damage in other groups. 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