On non-ideal simple portal frame structural model: Experimental results under a non-ideal excitation

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dc.contributor.authorBalthazar, José Manoel [UNESP]
dc.contributor.authorBrasil, RMLRF
dc.contributor.authorGarzeri, F. J.
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:21:38Z
dc.date.available2014-05-20T15:21:38Z
dc.date.issued2004-01-01
dc.description.abstractWe present measurements of the non-linear oscillations of a portal frame foundation for a non-ideal motor. We consider a three-time redundant structure with two columns, clamped in their bases and a horizontal beam. An electrical unbalanced motor is mounted at mid span of the beam. Two non-linear phenomena are studied: a) mode saturation and energy transfer between modes; b) interaction between high amplitude motions of the structure and the rotation regime of a real limited power motor. The dynamic characteristics of the structure were chosen to have one-to-two internal resonance between the anti-symmetrical mode (sway motions) and the first symmetrical mode natural frequencies. As the excitation frequency reaches near resonance conditions with the 2nd natural frequency, the amplitude of this mode grows up to a certain level and then it saturates. The surplus energy pumped into the system is transferred to the sway mode, which experiences a sudden increase in its amplitude. Energy is transformed from low amplitude high frequency motion into high amplitude low frequency motion. Such a transformation is potentially dangerous.We consider the fact that real motors, such as the one used in this study, have limited power output. In this case, this energy source is said to be non-ideal, in contrast to the ideal source whose amplitude and frequency are independent of the motion of the structure. Our experimental research detected the Sommerfeld Effect: as the motor accelerates to reach near resonant conditions, a considerable part of its output energy is consumed to generate large amplitude motions of the structure and not to increase its own angular speed. For certain parameters of the system, the motor can get stuck at resonance not having enough power to reach higher rotation regimes. If some more power is available, jump phenomena may occur from near resonance to considerably higher motor speed regimes, no stable motions being possible between these two.en
dc.description.affiliationState Univ São Paulo Rio Claro, BR-13500230 Rio Claro, SP, Brazil
dc.description.affiliationUnespState Univ São Paulo Rio Claro, BR-13500230 Rio Claro, SP, Brazil
dc.format.extent51-57
dc.identifierhttp://dx.doi.org/10.4028/www.scientific.net/AMM.1-2.51
dc.identifier.citationAdvances In Experimental Mechanics. Stafa-zurich: Trans Tech Publications Ltd, v. 1-2, p. 51-57, 2004.
dc.identifier.doi10.4028/www.scientific.net/AMM.1-2.51
dc.identifier.issn1660-9336
dc.identifier.urihttp://hdl.handle.net/11449/32753
dc.identifier.wosWOS:000228265900007
dc.language.isoeng
dc.publisherTrans Tech Publications Ltd
dc.relation.ispartofAdvances In Experimental Mechanics
dc.relation.ispartofsjr0,117
dc.rights.accessRightsAcesso aberto
dc.sourceWeb of Science
dc.subjectexperimental analysispt
dc.subjectnon-ideal motorspt
dc.subjectnon-linear dynamicspt
dc.titleOn non-ideal simple portal frame structural model: Experimental results under a non-ideal excitationen
dc.typeTrabalho apresentado em evento
dcterms.licensehttp://www.ttp.net/Downloads.html
dcterms.rightsHolderTrans Tech Publications Ltd
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Rio Claropt

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