<p> Steady state response of a single degree of freedom system with impact damper, with the main emphasis of two impacts (symmetric or unsymmetric)/cycle motion, and its asymptotic stability criterion are derived analytically. Stability regions are determined for wide range of parameters of the impact damper by using digital computer. </p> <p> Experimental study is also made to verify the assumptions taken in the analytical solution and to obtain general response of the system for wide range of parameters of the impact damper. </p> <p> As a result, it is found that unsymmetric two impacts per cycle motion exists and is stable for a wide range of parameters of the impact damper. </p> <p> Also, it is found that three and four impacts/cycle motions exist and are stable. </p> <p> Stability boundaries are found to be a complicated function of the impact damper parameters. </p> / Thesis / Master of Engineering (MEngr)

The use of a tuned absorber to control the vibration amplitudes of a secondary system subjected to base excitation via a primary system is investigated computationally. A second investigation considers the use of an impact damper mounted on the tuned absorber to control vibration amplitudes of secondary system subjected to base excitation via the same primary system. A series of spreadsheet programs have been written to assist in the investigation of the two vibration control problems. Techniques for solving both closed form and numerical integration problems using spreadsheet macros are presented. The graphics capabilities of spreadsheets are used to present the results of batch case runs of different system parameters. User manuals for both series of programs have been written, fully explaining the programs and how they can be used as a basis for continued investigations of these and similar situations. / Thesis / Master of Engineering (ME) / This thesis has been partially OCRed.

<p> An extensive experimental study is made of the general behaviour of the impact dampers, using a mechanical model. Coefficient of restitution, Mass-ratio, and Gap-factor are the parameters which were changed during the course of investigation and their effects were observed. </p> <p> The noise level has been eliminated successfully. Dampers containing two particles in a single container are compared with single particles dampers and the latter are found to be relatively efficient. Results with the mass particle oscillating in the container filled with fluid indicate that friction forces acting on the mass-particle are detrimental to the efficiency of the damper. </p> / Thesis / Master of Engineering (ME)

L'objectif de cette thèse est d'étudier le contrôle passif des vibrations avec un absorbeur non linéaire de type Nonlinear Energy Sink (NES) à Vibro-Impact (VI). Plusieurs aspects ont été étudiés : l’influence des paramètres sur les régimes vibratoires observés, l’optimisation du design sous différentes excitations, l'application sur des systèmes vibratoires non linéaires et enfin l'étude de deux NES-VI en parallèle.Tout d'abord, l’influence des paramètres de design sur les régimes vibratoires et les bifurcations est étudiée de façon analytique, numérique et expérimentale. Ainsi différentes bifurcations et des réponses fortement modulées de type chaotique sont présentées.Ensuite, l’efficacité des régimes vibratoires est comparée, le mécanisme ainsi décrit constitue la base de l’optimisation du design de l’absorbeur face à différents types d’excitation.Le mécanisme d’activation du NES-VI est étudié analytiquement puis validé expérimentalement. Un critère d’optimisation du design est proposé, puis appliqué sur différents systèmes au comportement vibratoire non linéaire.Finalement, dans le but d’améliorer l’efficacité et la robustesse, le montage de deux NES-VI en parallèle est étudié expérimentalement. Le principe d’activation séparé est alors observé. / The objective of this thesis is to study the passive control of vibration by a Vibro-Impact (VI) Nonlinear Energy Sink (NES). Several aspects have been developed: the influence of parameters on response regimes, the optimization design mechanism under different excitations, the application to vibration control of nonlinear systems and the study of two VI NES in parallel.Firstly, the influence of parameters on response regimes and bifurcation is analytically, numerically and experimentally studied, respectively. Different bifurcation routes and chaotic strongly modulated response are presented.Then, the efficiency of typical response regimes is compared, and its mechanism lays the foundation for the optimization design of different parameters under different types of excitation.Thirdly, the activation characteristic of VI NES is analytically studied and experimentally validated. An optimization design criterion is proposed for the vibration control of nonlinear system.Finally, the vibration control by two VI NES in parallel is experimentally studied with the purpose of efficiency and robustness improvement. The principle of separate activation of VI NES is observed