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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Superharmonic nonlinear lateral vibrations of a segmented driveline incorporating a tuned damper excited by non-constant velocity joints

Browne, Michael 2009 May 1900 (has links)
Linear vibration measurement and analysis techniques have appeared to be sufficient with most vibration problems. This is partially due to the lack of proper identification of physical nonlinear dynamic responses. Therefore, as an example, a vehicle driveshaft exhibits a nonlinear super harmonic jump due to nonconstant velocity, NCV, joint excitation. Previously documented measurements or analytical predictions of vehicle driveshaft systems do not indicate nonlinear jump as a typical vibration mode. The nonlinear jump was both measured on a driveshaft test rig and simulated with a correlated model reproduced the jump. Subsequent development of the applied moments and simplified equations of motion provided the basis for nonlinear analysis. The nonlinear analyses included bifurcation, Poincare, Lyapunov Exponent, and identification of multiple solutions. Previous analytical models of driveshafts incorporating NCV joints are typically simple lumped parameter models. Complexity of models produce significant processing costs to completing significant analysis, and therefore large DOF systems incorporating significant flexibility are not analyzed. Therefore, a generalized method for creating simplified equations of motion while retaining integrity of the base system was developed. This method includes modal coupling, modal modification, and modal truncation techniques applied with nonlinear constraint conditions. Correlation of resonances and simulation results to operating results were accomplished. Previous NCV joint analyses address only the torsional degree of freedom. Limited background on lateral excitations and vibrations exist, and primarily focus on friction in the NCV joint or significant applied load. Therefore, the secondary moment was developed from the NCV joint excitation for application to the driveshaft system. This derivation provides detailed understanding of the vibration harmonic excitations due to NCV joints operating at misalignment angles. The model provides a basis for completing nonlinear analysis studying the system in more detail. Bifurcation analysis identified ranges of misalignment angles and speeds that produced nonlinear responses. Lyapunov Exponent analysis identified that these ranges were chaotic in nature. In addition, these analyses isolated the nonlinear response to the addition of the ITD nonlinear stiffness. In summary, the system and analysis show how an ITD installed to attenuate unwanted vibrations can cause other objectionable nonlinear response characteristics.
182

Vibrations of plates with masses

Solov'ëv, Sergey I. 31 August 2006 (has links) (PDF)
This paper presents the investigation of the nonlinear eigenvalue problem describing free vibrations of plates with elastically attached masses. We study properties of eigenvalues and eigenfunctions and prove the existence theorem. Theoretical results are illustrated by numerical experiments.
183

Modélisation du frottement en pied d'aube par une approche fréquentielle

Nacivet, Samuel Jézéquel, Louis January 2002 (has links) (PDF)
Thèse de doctorat : sciences. Mécanique : Ecully, Ecole centrale de Lyon : 2002. / 103 réf.
184

Extension et reformulation du modèle SEA par la prise en compte de la répartition des énergies modales

Maxit, Laurent Guyader, Jean-Louis. January 2001 (has links)
Thèse doctorat : Acoustique : Villeurbanne, INSA : 2000. / Titre provenant de l'écran-titre. Bibliogr. p. 213-223.
185

Modélisation numérique de matériaux poreux hétérogènes application à l'absorption basse fréquence /

Castel, Franck Atalla, Noureddine. Sgard, Franck. January 2006 (has links)
Thèse doctorat : Acoustique : Villeurbanne, INSA : 2005. Thèse doctorat : Acoustique : Université de Sherbrooke (Canada) : 2005. / Thèse soutenue en co-tutelle. Titre provenant de l'écran-titre. Bibliogr. p. 197-202.
186

Dissipation de l'énergie en mécanique vibratoire opérateur d'hystérésis, phénomène métrique /

Al Majid, Ahmad Dufour, Regis. January 2004 (has links)
Thèse de doctorat : Génie mécanique : Villeurbanne, INSA : 2002. / Titre provenant de l'écran-titre. Bibliogr. p.138-149.
187

Contribution au diagnostic industriel de défauts de roulement et de balourd par techniques neuronales application à la machine asynchrone à cage /

Diouf, Saliou Madani, Kurosh. January 2007 (has links) (PDF)
Thèse de doctorat : Sciences de l'ingénieur. Génie informatique, automatique et traitement du signal : Paris 12 : 2007. / Titre provenant de l'écran-titre. 188 p. Bibliogr. : 36 réf.
188

Localisation et quantification des sources vibratoires dans le cadre d'une maintenance préventive conditionnelle en vue de fiabiliser le diagnostic et le suivi de l'endommagement des composants mécaniques tournants : application aux roulements à billes

Chiementin, Xavier Dron, Jean-Paul January 2007 (has links) (PDF)
Reproduction de : Thèse doctorat : Mécanique : Reims : 2007. / Titre provenant de l'écran titre. Bibliogr. f. 153-159.
189

Modélisation du frottement en pied d'aube par une approche fréquentielle

Nacivet, Samuel Jézéquel, Louis January 2002 (has links) (PDF)
Thèse de doctorat : sciences. Mécanique : Ecully, Ecole centrale de Lyon : 2002. / Titre provenant de l'écran-titre. 103 réf.
190

Comportement vibroacoustique des conduits modélisation, mesure et applications aux instruments de musique à vent /

Nief, Guillaume Gilbert, Joël January 2008 (has links) (PDF)
Reproduction de : Thèse de doctorat : Acoustique : Le Mans : 2008. / Titre provenant de l'écran-titre. Bibliogr. p. 117-121.

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