Conventional isolation models deal with massless isolators, which tend to overestimate the isolator performance because they neglect the internal resonances (IRs) due to the inertia of the isolator. Previous researches on the IR problem is not adequate because they only discussed this problem in terms of vibration based on single degree-of-freedom (SDOF) models. These studies did not reveal the importance of the IRs, especially from the perspective of the noise radiation. This dissertation is novel compared to previous studies in the following ways: (a) a three-DOF (3DOF) model, which better represents practical vibration systems, is employed to investigate the importance of the IRs; (b) the IR problem is studied considering both vibration and noise radiation; and (c) passive and hybrid control approaches using dynamic vibration absorbers (DVAs) to suppress the IRs are investigated and their potential demonstrated. The 3DOF analytical model consists of a rigid primary mass connected to a flexible foundation through three isolators. To include the IRs, the isolator is modeled as a continuous rod with longitudinal motion. The force transmissibility through each isolator and the radiated sound power of the foundation are two criteria used to show the effects and significance of the IRs on isolator performance. Passive and hybrid DVAs embedded in the isolator are investigated to suppress the IRs. In the passive approach, two DVAs are implemented and their parameters are selected so that the IRs can be effectively attenuated without significantly degrading the isolator performance at some other frequencies that are also of interest. It is demonstrated that the passive DVA enhanced isolator performs much better than the conventional isolator in the high frequency range where the IRs occur. The isolator performance is further enhanced by inserting an active force pair between the two passive DVA masses, forming the hybrid control approach. The effectiveness and the practical potential of the hybrid system are demonstrated using a feedforward control algorithm. It is shown that this hybrid control approach not only is able to maintain the performance of the passive approach, but also significantly improve the isolator performance at low frequencies. / Ph. D.

This research deals with the second harmonic generation of Lamb waves in nonlinear elastic, homogeneous, isotropic plates. These waves find current applications in the field of ultrasonic, nondestructive testing and evaluation of materials. The second harmonic Lamb wave generation is investigated analytically in order to provide information on suitable excitation modes maximizing the second harmonic amplitude. Using an existing solution for the problem of second harmonic generation in wave guides, the solution is explained for the plate and examined as to the symmetry properties of the second harmonic wave, since published results are contradictory. It is shown that the cross-modal generation of a symmetric secondary mode by an antisymmetric primary mode is possible. Modes showing internal resonance, whose conditions are nonzero power flux from the primary wave and phase velocity matching, are shown to be most useful for measurements. In addition, group velocity matching is required. A material-independent analysis of the linear Lamb mode theory provides mode types satisfying all three requirements. Using the example of an aluminum plate, the found internally resonant modes are evaluated with regard to the rate of second harmonic generation and practical issues such as excitability and ease of measurement. Pros and cons of each mode type are presented.

Cette recherche met en évidence l'importance de la sensorialité dans le traiement des enfants autistes. Je propose la notion de co-sensualité en tant qu'organisateur de la relation de type primaire et rends compte du rôle qu'elle joue dans l'émergence du Moi. A partir d'un dispositif thérapeutique nommé "Boîte de résonance interne" qui s'appuie sur des postulats psychanalytiques autour du Moi-peau, la fonction contenant-contenu-conteneur et les enveloppes physiques, articulées au concept de dialogue tonico-émotionnel et d'accordage affectif. C'est la figuration d'un espace contenant susceptible de mobiliser la sensorialité tactile, sonore, visuelle, olfactive et kinesthésique dans une dynamique de rencontre visant une libidinisation du lien de type primaire et favorisant l'intériorisation de la fonction contenant et la constitution du Moi. Par l'étude de quatre cas cliniques, je mets en évidence la place que cette notion peut occuper dans le travail thérapeutique tant dans la mobilisation de la pulsion d'attachement comme dans la constitution du Moi corporel et psychique. Je propose l'idée que dans la co-sensualité, l'expérience sensorielle de deux corps, celui de l'enfant et celui du thérapeute s'inscrit dans un système de partage et de résonance affective et s'élabore à partir du travail de figuration proposé par le thérapeute. / The aim of this research is to point out the importance of sensoriality as means of intersubjective encounter starting from the notion of sensuality. I am tryng to show that this concept can take a function as organizer of a primary type relationship and the part it development of a therapeutic device that I have named inernal resonance box which is based on assumptions of psychoanalytic currents around the Ego-skin content-container function and the psychic envelopes articulated around notions of emotional adjustment and emotionally-tonic adjustment. I present this device, as representation of a space-content, able to mobilize the sensoriality such as touch, sound, visual,olfactory and kinesthetic in a dynamic encounter for the purpose of a libidinization of primary type link wich favours prymary internalization of the contenant function and structure of the Ego in both physical and psychological dimensions in relational dynamics. By studing four children who were followed in the internal resonance box, I point out the part that this notion plays in therapeutic work. I suggest the idea that in co-sensuality, the sensorial experience of two bodies, the child's and the therapist's, will be part of a sharing and "emotional resonance" system, developed from the representation work offered by therapist in the "content" position. / La presente investigación tiene por objetivo de mostrar la importancia de la sensorialidad como medio de encuentro ínter subjectiva, a través de la noción de co-sensualidad. Se trata de poner en evidencia la función que puede tomar como organizador de la relación primaria y el papel que desempeña en el advenimiento del Yo. Esta investigación trata de la construcción de un dispositivo terapéutico llamado “caja de resonancia interna” que se apoya sobre postulados del campo psicoanalítico alrededor del Yo-piel, la función contenante y contenedor, como también las envolturas psíquicas, en articulación a la noción de acorde afectivo y ajuste tónico-emocional.El dispositivo es considerado como una figuración de un espacio contenedor, susceptible de movilizar la sensorialidad táctil, sonora, visual, olfativa y kinestésica, en una dinámica de encuentro, a fines de libidinalización del vínculo relacional de tipo primario, el cual favoriza la interiorización de la función contenante y la constitución del Yo en sus dos dimensiones corporal y psíquica, en una dinámica relacional.Les propongo articulaciones conceptuales que permiten aclarar la noción de co-sensualidad y poner en evidencia su función en la estructuración de la relación inter subjetiva de tipo primario, en el marco del tratamiento de niños que presentan un funcionamiento de tipo autístico. A través el estudio de caso de cuatro situaciones clínicas, se pone en evidencia el sitio que la noción de co-sensualidad puede tomar en el trabajo terapéutico. Se propone la idea que en la co-sensualidad, la experiencia sensorial de dos cuerpos (terapeuta y niño) va inscribirse en un sistema de comunicación y de resonancia afectiva, elaborada sobre la base del trabajo de figuración del terapeuta que se halla en posición de “contenedor”. Se trata de mostrar el trabajo de traducción de la experiencia sensorial, operada por el terapeuta quien se apoya sobre su propia subjetividad y objetos internalizados. Los estudios de caso nos dejan pensar que la co-sensualidad está arraigada en un baño de cultura y de lengua pre-existente en el sujeto “contenedor”, y que es transmitido de manera inconsciente, dando origen a la emergencia de una subjetivación específica a cada individuo. Se considera la diversidad de modos de relación al mundo que se actualizan en el encuentro y que son vehiculados a través de los mecanismos de identificación adhesiva y proyectiva, actualizados en el trabajo terapéutico de figuración.