The application of laser Doppler vibrometry to high speed rotating structures has been hampered by technical limitations. Whereas full-field three-dimensional velocity measurements can be made on stationary structures, the capability on rotating structures is limited to low speed, one-dimensional, steady state operation. This work describes the implementation of a self-tracking laser vibrometry system which overcomes many of the limitations of current techniques for vibration measurements on rotating structures. A model of the self-tracker is developed and used to predict the effects of static misalignments on the position and velocity errors. These predictions are supported by experimental results and simplified models of the self-tracker. NOTE: (02/2011) An updated copy of this ETD was added after there were patron reports of problems with the file. / Ph. D.

Insects can cause economic and environmental damages by transmitting bacterial pathogens to plants, making the use of control and prevention measures imperative. On the other hand, methods aimed at preventing crop pests’ outbreaks, such as tilling and insecticide applications, pose a threat to human and ecosystems health. Innovative and more sustainable control methods are therefore urgently needed to address farmers’ needs and preserve ecosystem services provided by biodiversity. Biotremology is an emerging science that studies the substrate-borne vibrational signals emitted by insects to communicate and interact with their others in the environment. As many insect pests rely on these signals to communicate, their behaviour can be manipulated by transmitting vibrations to the substrate where they thrive. Vibrational signals can, for instance, interfere with target’s behaviours such as mating, feeding, and residence time on the plant, and can therefore support integrated pest management strategies alternative to insecticides. In this work, I investigated the mating behaviour and vibrational communication of two insect vectors having an important economic impact: Philaenus spumarius (Hemiptera: Aphrophoridae) and Bactericera cockerelli (Hemiptera: Triozidae). I also provided novel insights regarding the vibrational manipulation of their behaviour. I characterised the sexual behaviour and associated vibrational signals of the meadow spittlebug P. spumarius, and I described other intraspecific interactions. I evaluated the correlation between the female signalling activity and development of the reproductive organs, suggesting that a vibrational mating disruption could be effective only if applied from the onset of egg maturation, which triggers the female proceptivity (from August onwards). Besides gathering behavioural data, I used occupancy models to estimate P. spumarius presence and detection probability in Trentino (Northern Italy), a rarely deployed approach to study insect distribution. Site covariates impacted P. spumarius detectability, suggesting that spittlebug presence can be overlooked if detection is not considered. As plant composition influences the presence and abundance of the spittlebug, I studied the association between P. spumarius and its host plants. Such information can support monitoring programs and control strategies aimed at reducing P. spumarius population in crops of interest by shaping the plant composition of the ground cover. After investigating the behaviours and the ecology of the spittlebug, I attempted to disrupt its feeding activity using vibrations, opening the gates for future research. In this regard, I combined for the first time biotremology with the Electrical Penetration Graph (EPG) technique. The tomato potato psyllid B. cockerelli is an important threat to New Zealand crops. Besides the characterisation of the pair formation process and associated vibrational signals, I used vibrations to disrupt mate finding by transmitting vibrations to the host plant. Given that the stimulus attracted male psyllids at small scale, this strategy is a feasible approach that could be implemented for use in fields and greenhouses. In this way, an innovative trapping and mating disruption device could join the farmers’ toolbox for monitoring and controlling B. cockerelli. In conclusion, I provided new information regarding the ethology of two insect vectors and suggested that there is room for applied biotremology to support sustainable management strategies.

A load-enhanced methodology has been proposed to enable the in situ detection, localization, and characterization of damage in metallic plate-like structures using Lamb waves. A baseline-free load-differential method using the delay-and-sum imaging algorithm is proposed for defect detection and localization. The term “load-differential” refers to the comparison of recorded ultrasonic signals at various levels of stress. Defect characterization is achieved by incorporating expected scattering information of guided waves interacting with defects into the minimum variance imaging algorithm, and a method for estimating such scattering patterns from the measurements of a sparse transducer array is developed. The estimation method includes signal preprocessing, extracting initial scattering values from baseline subtraction results, and obtaining the complete scattering matrix by applying radial basis function interpolation. The factors that cause estimation errors, such as the shape parameter used to form the basis function and the filling distance used in the interpolation, are discussed. The estimated scattering patterns from sparse array measurements agree reasonably well with laser wavefield data and are further used in the load-enhanced method. The results from fatigue tests show that the load-enhanced method is capable of detecting cracks, providing reasonable estimates of their localizations and orientations, and discriminating them from drilled holes, disbonds, and fastener tightness variations.

Les ondes acoustiques et électromagnétiques offrent des méthodes de caractérisation des matériaux très peu invasives. Souvent utilisées à l'aide de capteurs indépendants, l'approche développée ici est de proposer un résonateur multimodal acoustique et électromagnétique. Afin de répondre à une grande variété d'applications, le choix de l'élément actif piézo-électrique s'est porté sur un disque de quartz de coupe AT. L'étude s'articule autour des étapes aboutissant in fine à un capteur magnéto acoustique on-chip à excitation sans contact.L'étude théorique d'un capteur magnéto-acoustique à excitation inductive est tout d'abord réalisée pour un capteur chargé par un fluide visqueux. Ce capteur est constitué de trois éléments : une sonde radiofréquence (RF), un résonateur RF à fort facteur de qualité et le quartz sur lequel ont été déposées deux électrodes en anneau. Cette étude montre comment déduire la viscosité complexe du matériau étudié à partir de l'impédance électrique du système complet. Les mesures effectuées sur des mélanges étalons montrent une très bonne correspondance avec les résultats théoriques.L'intégration du résonateur RF sur l'élément piézo-électrique s'effectuant via des électrodes circulaires, une étude préliminaire est menée sur les ondes acoustiques pouvant être générées sur le quartz et leur interaction avec les électrodes. Les mesures de vibration par vibrométrie laser montrent que des ondes de Lamb sont générées dans une large gamme de fréquence (de 100 kHz à 20 MHz). L'analyse de la réponse impulsionnelle spatiale par transformée de Gabor 3D localise la source de ces ondes sur le bord des électrodes. Par ailleurs, l'étude du disque au fondamental montre une grande non-linéarité mécanique du quartz.Le modèle de résonateur RF plan multi-tour puis son intégration sur le disque de quartz du capteur magnéto-acoustique on-chip sont ensuite étudiés. Les résultats expérimentaux par mesure d'impédance et vibrométrie laser valident le modèle. La gamme de fréquence sélectionnée (entre 5 et 20 MHz) permet d'envisager des mesures micro-rhéologiques. / Acoustic and electromagnetic waves are key probing candidates for characterizing their propagation media with minimum perturbation. Often used with independent sensors based on specialized transducing materials, the approach developed here provides an on-ship multimodal sensor using the same sensing material for probing the acoustic and electromagnetic properties of the material. To meet a wide range of applications, the choice of the active piezoelectric element is carried out on an AT cut quartz. The study focuses on the steps leading in fine to an on-chip magneto-acoustic sensor with a contactless excitation.The theoretical study of a magneto-acoustic sensor inductively excited and loaded by a viscous fluid is first carried out. This sensor consists of three elements: a radio frequency (RF) sensor, a high quality factor RF resonator and a quartz on which two ring electrodes have been deposited. The complex viscosity of the studied material is derived from the electrical impedance of the complete system. The measurements carried on etalon viscoelastic materials show a good agreement with the theoretical results.The integration of the RF resonator on the piezoelectric element being via circular electrodes, a preliminary study is performed for determining the acoustic waves that can be generated in the quartz and their interaction with the electrodes. The laser vibrometry measurements indicate that Lamb waves are generated in a wide frequency range, from 100 kHz to 20 MHz. The analysis of the spatial pulse response of the sensor surface by 3D Gabor transform locates the source of these waves on the edge of the electrodes. Furthermore, the study of the disk at it fundamental frequency points out the high nonlinear mechanical behavior of the quartz.The plane RF multi-turn resonator and its integration on the quartz disk of the magneto-acoustic on-chip sensor are then studied. The experimental results of impedance and laser vibrometry measurements validate the proposed theoretical model. The selected frequency range (between 5 and 20 MHz) allows one to consider micro rheological measurements.

La stéréolithographie biphotonique (TPS) est une technique de microfabrication 3D basée sur la polymérisation par absorption biphotonique qui permet d’obtenir en une seule étape des structures 3D complexes avec des détails sub-100nm. Aujourd’hui, en raison des conditions spécifiques de fabrication liées à la TPS (fort flux, confinement spatial de la photoréaction,…), un des enjeux concerne le développement de matériaux fonctionnels compatibles avec ce procédé. Dans ce contexte, l’objectif de cette thèse a été de développer de nouveaux matériaux fonctionnels à base de polymères à empreintes moléculaires (MIP) pour élaborer des capteurs chimiques. Une première partie de ce travail a consisté à mettre en place différentes méthodes dédiées à la caractérisation des propriétés géométriques, chimiques et mécaniques des matériaux élaborés par TPS. Par exemple, la vibrométrie laser a été utilisée pour la première fois afin de sonder de façon non-invasive les propriétés mécaniques de microstructures réalisées par TPS. Dans un second temps, ce travail a été mis à profit pour étudier l’impact du processus de fabrication (i.e. conditions photoniques) ainsi que des paramètres physico-chimiques affectant la photoréaction (i.e. inhibition par oxygène et nature du monomère) sur les propriétés finales des matériaux. Enfin, en s’appuyant sur les résultats obtenus, des microcapteurs chimiques à base de MIP, à lecture optique ou mécanique, ont été fabriqués. Leurs propriétés de reconnaissance moléculaire, ainsi que leurs sélectivités ont été démontrées pour une molécule cible modèle (D-L-Phe). / The two-photon stereolithography (TPS) technique is a micro-nanofabrication method based on photopolymerization by two-photon absorption that allows in a single manufacturing step to obtain complex 3D structures with high-resolution details (sub-100nm). Due to the specific conditions of TPS process (intense photon flux, spatial confinement of the photoreaction…) one of the main concerns today is the development of functional materials compatible with the TPS. According to the aforementioned, the general objective of this thesis was to develop new functional materials based on molecularly imprinted polymers (MIP) to elaborate chemical microsensors. In the first step of this work, different methods were implemented to characterize the geometrical, chemical and mechanical properties of the materials synthesized by TPS. For example, laser-Doppler vibrometry was used for first time to evaluate the mechanical properties of microstructures fabricated by TPS in a non-invasive way. In the second step, the characterization methodology was used to study the impact of the manufacturing process (i.e. photonic conditions) and the physicochemical parameters that affect the photoreaction (i.e. oxygen inhibition and the nature of the monomer) and the final properties of the materials. Finally, the obtained results enabled the prototyping of chemical microsensors based on MIP. Their molecular recognition properties and their selectivity were demonstrated for the molecule (D-L-Phe) by an optical and a mechanical sensing method.