dc.contributor.advisor Nikravesh, Parviz E. en_US dc.contributor.author Ambrosio, Jorge Alberto Cadete dc.creator Ambrosio, Jorge Alberto Cadete en_US dc.date.accessioned 2011-10-31T17:42:10Z dc.date.available 2011-10-31T17:42:10Z dc.date.issued 1991 en_US dc.identifier.uri http://hdl.handle.net/10150/185578 dc.description.abstract The problem of formulating and numerically solving the equations of motion of flexible multibody systems for application to structural impact is considered in this dissertation. As an alternative to experimental tests and to numerical procedures such as hybrid models and finite element methods, multibody dynamics contains the ingredients for efficient crash analysis of these problems provided that a proper description of the deformations of the system components is included. Based on the principles of continuum mechanics, updated and total Lagrangian formulations are used to derive the equations of motion for a flexible body. The finite element method is applied to these equations in order to obtain a numerical solution of the problem. It is shown that the use of convected coordinate systems not only simplifies the form of the flexible body equations of motion, but it also lowers the requirements for objectivity of the material law. A simpler form of the finite element equations of motion is obtained when a lumped mass formulation is used, and the nodal accelerations are expressed in a nonmoving reference frame. In this form, not only the geometric and material nonlinear behavior of the flexible body is accounted for, but also the inertial coupling between the gross motion and the distributed flexibility is preserved. A reduction on the number of coordinates describing the flexible body is achieved with the application of the Guyan condensation technique or the modal superposition method. For partially flexible bodies with a small deformable part, an efficient kinetostatic method is derived assuming that the deformable part is massless. The equations of motion of the complete multibody system are formulated in terms of joint coordinates. The necessary velocity transformations between the set of independent velocities and the dependent velocities are derived. Special emphasis is paid to the formulation of the constraint equations of kinematic joints involving flexible bodies. The dynamics of a truck rollover are studied in order to illustrate the efficiency of the developed methodology. Several simulations are performed using a general purpose multibody dynamics analysis code. dc.language.iso en en_US dc.publisher The University of Arizona. en_US dc.rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. en_US dc.subject Dissertations, Academic en_US dc.subject Mechanical engineering en_US dc.title Elastic-plastic large deformation of flexible multibody systems in crash analysis. en_US dc.type text en_US dc.type Dissertation-Reproduction (electronic) en_US dc.identifier.oclc 711709286 en_US thesis.degree.grantor University of Arizona en_US thesis.degree.level doctoral en_US dc.contributor.committeemember Kamel, Hussein A. en_US dc.contributor.committeemember Simon, Bruce R. en_US dc.contributor.committeemember Arabyan, Ara en_US dc.identifier.proquest 9200029 en_US thesis.degree.discipline Aerospace and Mechanical Engineering en_US thesis.degree.discipline Graduate College en_US thesis.degree.name Ph.D. en_US refterms.dateFOA 2018-08-23T04:37:34Z html.description.abstract The problem of formulating and numerically solving the equations of motion of flexible multibody systems for application to structural impact is considered in this dissertation. As an alternative to experimental tests and to numerical procedures such as hybrid models and finite element methods, multibody dynamics contains the ingredients for efficient crash analysis of these problems provided that a proper description of the deformations of the system components is included. Based on the principles of continuum mechanics, updated and total Lagrangian formulations are used to derive the equations of motion for a flexible body. The finite element method is applied to these equations in order to obtain a numerical solution of the problem. It is shown that the use of convected coordinate systems not only simplifies the form of the flexible body equations of motion, but it also lowers the requirements for objectivity of the material law. A simpler form of the finite element equations of motion is obtained when a lumped mass formulation is used, and the nodal accelerations are expressed in a nonmoving reference frame. In this form, not only the geometric and material nonlinear behavior of the flexible body is accounted for, but also the inertial coupling between the gross motion and the distributed flexibility is preserved. A reduction on the number of coordinates describing the flexible body is achieved with the application of the Guyan condensation technique or the modal superposition method. For partially flexible bodies with a small deformable part, an efficient kinetostatic method is derived assuming that the deformable part is massless. The equations of motion of the complete multibody system are formulated in terms of joint coordinates. The necessary velocity transformations between the set of independent velocities and the dependent velocities are derived. Special emphasis is paid to the formulation of the constraint equations of kinematic joints involving flexible bodies. The dynamics of a truck rollover are studied in order to illustrate the efficiency of the developed methodology. Several simulations are performed using a general purpose multibody dynamics analysis code.
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