{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/105996"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/105996","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Prediction of high-speed shaft natural frequencies employing harmonic excitation","abstract":"A shaft and bearing system was developed with natural frequencies in the range of 8,000 to 60,000 rpm for the purpose of determining the practicality of low-speed harmonic excitation of high-speed natural frequencies. The analytical development and analysis utilized SPAR, a finite element program, and a bearing stiffness program to determine frequencies for the first through fourth harmonics of natural frequencies under 60,000 rpm. A misaligned flexible disc coupling was used to input a forcing function with a frequency of N times the running speed and thereby excite the natural frequencies in the Nth harmonic at the running speed. Most of the analytical results had corresponding experimental results; however, many increased vibration levels did not correlate with analytical results. Four frequency response plots are presented. A comparison of these plots and analytical results are presented in the form of a Campbell diagram. Although the experimental results are not supportive enough to be conclusive, they do indicate that low-speed harmonic excitation may be a method of predicting high-speed natural frequencies. Major difficulties were encountered in the experimental program which are described, and some alternative investigations are proposed.","abstract_html":"A shaft and bearing system was developed with natural frequencies in the range of 8,000 to 60,000 rpm for the purpose of determining the practicality of low-speed harmonic excitation of high-speed natural frequencies. The analytical development and analysis utilized SPAR, a finite element program, and a bearing stiffness program to determine frequencies for the first through fourth harmonics of natural frequencies under 60,000 rpm. A misaligned flexible disc coupling was used to input a forcing function with a frequency of N times the running speed and thereby excite the natural frequencies in the Nth harmonic at the running speed. Most of the analytical results had corresponding experimental results; however, many increased vibration levels did not correlate with analytical results. Four frequency response plots are presented. A comparison of these plots and analytical results are presented in the form of a Campbell diagram. Although the experimental results are not supportive enough to be conclusive, they do indicate that low-speed harmonic excitation may be a method of predicting high-speed natural frequencies. Major difficulties were encountered in the experimental program which are described, and some alternative investigations are proposed.","abstract_has_math":false,"creators":["Lehmann, Katherine Jeanne"],"institution":"Virginia Polytechnic Institute and State University","degree_name":"M.S.","degree_level":"masters","degree_discipline":"Mechanical Engineering","degree_department":"Mechanical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1983,"date_issued":"1983","date_published":"1983","updated_at":"2026-07-22T22:20:35Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/105996","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Lehmann, Katherine Jeanne"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2021-10-26T20:09:46Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2021-10-26T20:09:46Z"]},{"key":"dc:date.issued","label":"Date","values":["1983"]},{"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":["Mechanical 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/10919/105996"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A shaft and bearing system was developed with natural frequencies in the range of 8,000 to 60,000 rpm for the purpose of determining the practicality of low-speed harmonic excitation of high-speed natural frequencies. The analytical development and analysis utilized SPAR, a finite element program, and a bearing stiffness program to determine frequencies for the first through fourth harmonics of natural frequencies under 60,000 rpm. A misaligned flexible disc coupling was used to input a forcing function with a frequency of N times the running speed and thereby excite the natural frequencies in the Nth harmonic at the running speed. Most of the analytical results had corresponding experimental results; however, many increased vibration levels did not correlate with analytical results. Four frequency response plots are presented. A comparison of these plots and analytical results are presented in the form of a Campbell diagram. Although the experimental results are not supportive enough to be conclusive, they do indicate that low-speed harmonic excitation may be a method of predicting high-speed natural frequencies. Major difficulties were encountered in the experimental program which are described, and some alternative investigations are proposed."]},{"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":["Prediction of high-speed shaft natural frequencies employing harmonic excitation"]}]}],"canonical_facts":{"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Lehmann, Katherine Jeanne"],"dc:date.accessioned":["2021-10-26T20:09:46Z"],"dc:date.available":["2021-10-26T20:09:46Z"],"dc:date.issued":["1983"],"dc:description.abstract":["A shaft and bearing system was developed with natural frequencies in the range of 8,000 to 60,000 rpm for the purpose of determining the practicality of low-speed harmonic excitation of high-speed natural frequencies. The analytical development and analysis utilized SPAR, a finite element program, and a bearing stiffness program to determine frequencies for the first through fourth harmonics of natural frequencies under 60,000 rpm. A misaligned flexible disc coupling was used to input a forcing function with a frequency of N times the running speed and thereby excite the natural frequencies in the Nth harmonic at the running speed. Most of the analytical results had corresponding experimental results; however, many increased vibration levels did not correlate with analytical results. Four frequency response plots are presented. A comparison of these plots and analytical results are presented in the form of a Campbell diagram. Although the experimental results are not supportive enough to be conclusive, they do indicate that low-speed harmonic excitation may be a method of predicting high-speed natural frequencies. Major difficulties were encountered in the experimental program which are described, and some alternative investigations are proposed."],"dc:description.degree":["M.S."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/105996"],"dc:language.iso":["en"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Prediction of high-speed shaft natural frequencies employing harmonic excitation"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["M.S."],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:35Z"}