Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-05-24T18:14:58Z No. of bitstreams: 1 texto completo.pdf: 5299836 bytes, checksum: 2701dbf5c59053f49a6b8e1ed8185376 (MD5) / Approved for entry into archive by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-05-24T18:15:10Z (GMT) No. of bitstreams: 1 texto completo.pdf: 5299836 bytes, checksum: 2701dbf5c59053f49a6b8e1ed8185376 (MD5) / Approved for entry into archive by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-05-24T18:15:21Z (GMT) No. of bitstreams: 1 texto completo.pdf: 5299836 bytes, checksum: 2701dbf5c59053f49a6b8e1ed8185376 (MD5) / Made available in DSpace on 2018-05-24T18:15:30Z (GMT). No. of bitstreams: 1 texto completo.pdf: 5299836 bytes, checksum: 2701dbf5c59053f49a6b8e1ed8185376 (MD5) Previous issue date: 2017-04 / As principais características que os tornam uma escolha vantajosa estão diretamente relacionadas aos materiais viscoelásticos utilizados na construção desses sistemas auxiliares. Esta tese de doutorado versa sobre a modelagem de neutralizadores dinâmicos aplicados ao problema de vibrações torcionais em rotores, cujo resultado final é definir os parâmetros do material viscoelástico e geométricos do neutralizador, ou seja, nesta abordagem, o material é definido posteriormente, a partir da resposta do sistema físico, obtida através dos métodos de análise modal ou elementos finitos. Dessa forma, pode-se selecionar ou, eventualmente, sintetizar o elastômero que melhor se adapte ao problema em tela. Logo, é essa a característica que diferencia o modelo proposto nessa pesquisa de outros modelos já conhecidos, nos quais os parâmetros do sistema auxiliar são determinados a partir de um material pré-selecionado. O comportamento dinâmico do material viscoelástico linear foi descrito através do modelo fracionário de quatro parâmetros e para validar os resultados dessa modelagem foi utilizada uma bancada de rotodinâmica, a qual permitiu avaliar o neutralizador em movimento sob o efeito de vibração torcional. A introdução do forçamento de torção se deu por meio de um sistema de excitação angular controlado remotamente. A solução para aplicar esse tipo excitação supera, dessa forma, algumas das dificuldades da análise torcional com o sistema girando. Os resultados comprovam a eficácia do modelo fracionário proposto e evidenciam o potencial do neutralizador viscoelástico para o controle de vibrações torcionais em rotores. / The main characteristics that make them an advantageous choice are directly related to the viscoelastic materials used in the construction of these auxiliary systems. This doctoral thesis deals with the modeling of dynamic neutralizers applied to the prob- lem of torsional vibrations in rotors, the final result of which is to define the viscoelastic and geometric parameters of the neutralizer, that is, in this approach, the material is defined later, from the Response of the physical system, obtained through modal analysis methods or finite elements. In this way, one can select or, eventually, synthesize the elastomer that best suits the onscreen problem. Therefore, this is the characteristic that differentiates the model proposed in this research from other already known models, in which the parameters of the auxiliary system are determined from a pre-selected material. The dynamic behavior of the linear viscoelastic material was described through the fractional model of four parameters and to validate the results of this modeling, a rotodynamic workbench was used, which allowed to evaluate the neutralizer in motion under the effect of torsional vibration. The introduction of torsional forcing was done by means of a remotely controlled angular excitation system. The solution to apply this excitation type overcomes, therefore, some of the difficulties of the torsional analysis with the spinning system. The results prove the effectiveness of the proposed fractional model and show the potential of the viscoelastic neutralizer for the control of torsional vibrations in rotors.

<p>The report handles the transmission of signals from piezoresistive pressuresensors and thermocouple from a rotating object. </p><p>This report also evaluates the possibility to collect data in a datalogger that rotates with the object. Telemetrics was previously used for signaltransmission in Finspång, therefore there has been no tests considering preassure measuring. One transmitting method handled in this report is transmission through a slipring connection. </p><p>One test with a slipring connection was performed for transmitting signals from a piezoresistive preassuresensor. All parts were mounted on a disc which rotated at 4000 rpm. Measurements were made of static and dynamic preassure. The report also contains a description of the equipment used for the test, and how it was constructed.</p> / <p>Rapporten tar upp överföring av signaler från piezoresistiva tryckgivare samt termoelement från ett roterande objekt. </p><p>I rapporten redovisas också om det är möjligt att samla in mätdata i en datalogger som roterar med objektet. Eftersom man, i Finspång, tidigare har använt telemetri för signalöverföring från termoelement så har tryckmätning inte provats. Därför har denna metod inte tagits med i rapporten. En överföringsmetod som tas upp i rapporten är överföring med släpring. </p><p>Ett prov genomfördes med en släpring för överföring av signaler från en piezoresistiv tryckgivare. Allt monterades på en skiva som roterades upp till 4 000 varv/min. Det som mättes var statiskt och dynamiskt tryck. I rapporten finns det beskrivet vilken utrustning som använts vid provet och hur den är konstruerad.</p>

The report handles the transmission of signals from piezoresistive pressuresensors and thermocouple from a rotating object. This report also evaluates the possibility to collect data in a datalogger that rotates with the object. Telemetrics was previously used for signaltransmission in Finspång, therefore there has been no tests considering preassure measuring. One transmitting method handled in this report is transmission through a slipring connection. One test with a slipring connection was performed for transmitting signals from a piezoresistive preassuresensor. All parts were mounted on a disc which rotated at 4000 rpm. Measurements were made of static and dynamic preassure. The report also contains a description of the equipment used for the test, and how it was constructed. / Rapporten tar upp överföring av signaler från piezoresistiva tryckgivare samt termoelement från ett roterande objekt. I rapporten redovisas också om det är möjligt att samla in mätdata i en datalogger som roterar med objektet. Eftersom man, i Finspång, tidigare har använt telemetri för signalöverföring från termoelement så har tryckmätning inte provats. Därför har denna metod inte tagits med i rapporten. En överföringsmetod som tas upp i rapporten är överföring med släpring. Ett prov genomfördes med en släpring för överföring av signaler från en piezoresistiv tryckgivare. Allt monterades på en skiva som roterades upp till 4 000 varv/min. Det som mättes var statiskt och dynamiskt tryck. I rapporten finns det beskrivet vilken utrustning som använts vid provet och hur den är konstruerad.