Contributions to the theory of machine dynamics.
Item
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Title
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Contributions to the theory of machine dynamics.
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Identifier
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AAI9315516
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identifier
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9315516
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Creator
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Xu, Tao.
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Contributor
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Adviser: Gerard G. Lowen
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Date
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1993
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Language
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English
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Publisher
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City University of New York.
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Subject
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Engineering, Mechanical
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Abstract
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Certain contributions to the theory of machine dynamics, which were inspired by a previous investigation into the dynamic behavior of a press feed mechanism, were made: (1) A new, simplified, mathematical model of the complete multi-regime per cycle machine was developed. The ability to obtain a fully analytical solution allowed the exploration of the all-important transient components of the responses during the feeding stroke. Further, the solution clarified the relationship between the resulting system frequencies and the individual stand-alone frequencies of the elastic components of the mechanism. (2) Based on an energy dissipation study as well as comparison with experimentally obtained responses of the sprag clutch of the mechanism, it was shown that a non-linear damping force, which is a function of both velocity and displacement, is superior to a linear one when dealing with non-linear stiffness systems. (3) A new and complete mathematical model for a sprag clutch was devised. By postulating a two point Hertzian contact at each sprag-race interface, the experimentally obtained torque-displacement relationship could be theoretically duplicated. (4) A practical analytical approach for the determination of the transient responses in elastic mechanisms was given. Based on mathematical work by E. T. Whittaker, they were obtained by the determination of the characteristic exponent in the stable regions of the Floquet solution to the Hill's equations involved. Several sample computations showed that the transient responses may vary from near-periodic to totally aperiodic.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
