{"id":{"repo_id":"ohiolink","oai_identifier":"oai:etd.ohiolink.edu:osu1363195868"},"canonical_url":"https://search.dev.ndltd.org/etd/ohiolink/oai:etd.ohiolink.edu:osu1363195868","repository":{"repo_id":"ohiolink","name":"OhioLINK","base_url":"https://etd.ohiolink.edu/acprod/odb_etd/ws/oai/oai"},"display":{"title":"Isothermal Fatigue Life Prediction Techniques","abstract":"Substantial progress has been made in advancing a pre-existing energy-based fatigue life prediction method into a powerful tool for real-world application through three distinct analyses, resulting in considerable improvements to the fidelity and capability of the existing model. First, a torsional fatigue life prediction method with consideration for the identification and incorporation of loading multiaxiality was developed and validated against experimental results from testing of Aluminum 6061-T6 specimens at room temperature. Second, a unique isothermal-mechanical fatigue life testing capability was constructed and utilized in the development of an isothermal-mechanical fatigue life prediction method. This method was validated against experimental data generated from testing of Aluminum 6061-T6 specimens at multiple operating temperatures. Third, alternative quasi-static and dynamic constitutive relationships were applied to the isothermal-mechanical fatigue life prediction method. The accuracy of each new relationship was verified against experimental data generated from testing of two material systems with dissimilar properties: Aluminum 6061-T6 at multiple operating temperatures and Titanium 6Al-4V at room temperature. Each investigation builds upon a previously-developed energy-based life prediction capability, which states: the total strain energy dissipated during both a quasi-static process and a dynamic process are equivalent and a fundamental property of the material. Through these three analyses, the energy-based life prediction framework has acquired the capability of assessing the fatigue life of structures subjected to unplanned multiaxial loading and elevated isothermal operating temperatures; furthermore, alternative constitutive relationships have been successfully employed in improving the fidelity of the life prediction models. This work represents considerable advancements of the energy-based method, and provides a firm foundation for the growth of the energy-based life prediction framework into the thermo-mechanical fatigue regime. This future work will utilize many of the models developed for isothermal-mechanical fatigue; additionally, the isothermal-mechanical testing capability will be readily modified to perform thermo-mechanical fatigue.","abstract_html":"Substantial progress has been made in advancing a pre-existing energy-based fatigue life prediction method into a powerful tool for real-world application through three distinct analyses, resulting in considerable improvements to the fidelity and capability of the existing model. First, a torsional fatigue life prediction method with consideration for the identification and incorporation of loading multiaxiality was developed and validated against experimental results from testing of Aluminum 6061-T6 specimens at room temperature. Second, a unique isothermal-mechanical fatigue life testing capability was constructed and utilized in the development of an isothermal-mechanical fatigue life prediction method. This method was validated against experimental data generated from testing of Aluminum 6061-T6 specimens at multiple operating temperatures. Third, alternative quasi-static and dynamic constitutive relationships were applied to the isothermal-mechanical fatigue life prediction method. The accuracy of each new relationship was verified against experimental data generated from testing of two material systems with dissimilar properties: Aluminum 6061-T6 at multiple operating temperatures and Titanium 6Al-4V at room temperature. Each investigation builds upon a previously-developed energy-based life prediction capability, which states: the total strain energy dissipated during both a quasi-static process and a dynamic process are equivalent and a fundamental property of the material. Through these three analyses, the energy-based life prediction framework has acquired the capability of assessing the fatigue life of structures subjected to unplanned multiaxial loading and elevated isothermal operating temperatures; furthermore, alternative constitutive relationships have been successfully employed in improving the fidelity of the life prediction models. This work represents considerable advancements of the energy-based method, and provides a firm foundation for the growth of the energy-based life prediction framework into the thermo-mechanical fatigue regime. This future work will utilize many of the models developed for isothermal-mechanical fatigue; additionally, the isothermal-mechanical testing capability will be readily modified to perform thermo-mechanical fatigue.","abstract_has_math":false,"creators":["Wertz, John Nicholas"],"institution":"The Ohio State University","degree_name":"Doctor of Philosophy","degree_level":"doctoral","degree_discipline":"Aero/Astro Engineering","degree_department":null,"school":null,"contributors":["Shen, Mo-How Herman"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-05-24","date_published":"2013-05-24","updated_at":"2026-07-24T03:36:39Z","subjects":["Aerospace Materials","Aerospace Engineering","fatigue","fatigue lifing","life prediction","energy-based","isothermal"],"languages":["English"],"rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://rave.ohiolink.edu/etdc/view?acc_num=osu1363195868","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Shen, Mo-How Herman"]},{"key":"dc:creator","label":"Author","values":["Wertz, John Nicholas"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-05-24"]},{"key":"dc:publisher","label":"Institution","values":["The Ohio State University / OhioLINK"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aero/Astro Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["The Ohio State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Aerospace Materials","Aerospace Engineering","fatigue","fatigue lifing","life prediction","energy-based","isothermal"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://rave.ohiolink.edu/etdc/view?acc_num=osu1363195868"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Substantial progress has been made in advancing a pre-existing energy-based fatigue life prediction method into a powerful tool for real-world application through three distinct analyses, resulting in considerable improvements to the fidelity and capability of the existing model. First, a torsional fatigue life prediction method with consideration for the identification and incorporation of loading multiaxiality was developed and validated against experimental results from testing of Aluminum 6061-T6 specimens at room temperature. Second, a unique isothermal-mechanical fatigue life testing capability was constructed and utilized in the development of an isothermal-mechanical fatigue life prediction method. This method was validated against experimental data generated from testing of Aluminum 6061-T6 specimens at multiple operating temperatures. Third, alternative quasi-static and dynamic constitutive relationships were applied to the isothermal-mechanical fatigue life prediction method. The accuracy of each new relationship was verified against experimental data generated from testing of two material systems with dissimilar properties: Aluminum 6061-T6 at multiple operating temperatures and Titanium 6Al-4V at room temperature. Each investigation builds upon a previously-developed energy-based life prediction capability, which states: the total strain energy dissipated during both a quasi-static process and a dynamic process are equivalent and a fundamental property of the material. Through these three analyses, the energy-based life prediction framework has acquired the capability of assessing the fatigue life of structures subjected to unplanned multiaxial loading and elevated isothermal operating temperatures; furthermore, alternative constitutive relationships have been successfully employed in improving the fidelity of the life prediction models. This work represents considerable advancements of the energy-based method, and provides a firm foundation for the growth of the energy-based life prediction framework into the thermo-mechanical fatigue regime. This future work will utilize many of the models developed for isothermal-mechanical fatigue; additionally, the isothermal-mechanical testing capability will be readily modified to perform thermo-mechanical fatigue."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf","p.146","6.94 MB"]},{"key":"dc:title","label":"Title","values":["Isothermal Fatigue Life Prediction Techniques"]}]}],"canonical_facts":{"dc:contributor":["Shen, Mo-How Herman"],"dc:creator":["Wertz, John Nicholas"],"dc:date":["2013-05-24"],"dc:description":["Substantial progress has been made in advancing a pre-existing energy-based fatigue life prediction method into a powerful tool for real-world application through three distinct analyses, resulting in considerable improvements to the fidelity and capability of the existing model. First, a torsional fatigue life prediction method with consideration for the identification and incorporation of loading multiaxiality was developed and validated against experimental results from testing of Aluminum 6061-T6 specimens at room temperature. Second, a unique isothermal-mechanical fatigue life testing capability was constructed and utilized in the development of an isothermal-mechanical fatigue life prediction method. This method was validated against experimental data generated from testing of Aluminum 6061-T6 specimens at multiple operating temperatures. Third, alternative quasi-static and dynamic constitutive relationships were applied to the isothermal-mechanical fatigue life prediction method. The accuracy of each new relationship was verified against experimental data generated from testing of two material systems with dissimilar properties: Aluminum 6061-T6 at multiple operating temperatures and Titanium 6Al-4V at room temperature. Each investigation builds upon a previously-developed energy-based life prediction capability, which states: the total strain energy dissipated during both a quasi-static process and a dynamic process are equivalent and a fundamental property of the material. Through these three analyses, the energy-based life prediction framework has acquired the capability of assessing the fatigue life of structures subjected to unplanned multiaxial loading and elevated isothermal operating temperatures; furthermore, alternative constitutive relationships have been successfully employed in improving the fidelity of the life prediction models. This work represents considerable advancements of the energy-based method, and provides a firm foundation for the growth of the energy-based life prediction framework into the thermo-mechanical fatigue regime. This future work will utilize many of the models developed for isothermal-mechanical fatigue; additionally, the isothermal-mechanical testing capability will be readily modified to perform thermo-mechanical fatigue."],"dc:format":["application/pdf","p.146","6.94 MB"],"dc:identifier":["http://rave.ohiolink.edu/etdc/view?acc_num=osu1363195868"],"dc:language":["English"],"dc:publisher":["The Ohio State University / OhioLINK"],"dc:rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"dc:subject":["Aerospace Materials","Aerospace Engineering","fatigue","fatigue lifing","life prediction","energy-based","isothermal"],"dc:title":["Isothermal Fatigue Life Prediction Techniques"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Aero/Astro Engineering"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["The Ohio State University"]},"updated_at":"2026-07-24T03:36:39Z"}