This thesis represents the work that has been done by the author during his Master of Engineering Science candidature in the area of vibration control of flexible structures at the School of Mechanical Engineering, The University of Adelaide, between March 2003 and June 2004. The aim of this research is to further extend the application of the Spatial Control Approach for two-dimensional flexible structures for attenuating global structural vibration with the possible implication of reduction in noise radiation. The research was concentrated on a simply supported thin flexible plate, using piezoelectric ceramic materials as actuators and sensors. In this work, active controllers were designed for the purpose of controlling only the first five vibration modes (0-500Hz) of the plate. A spatial controller was designed to minimize the total energy of the spatially distributed signal, which is reflected by the spatial H2 norm of the transfer function from the disturbance signal to the vibration output at every point over the plate. This approach ensures the vibration contributed by all the in bandwidth (0-500 Hz) vibration modes is minimized, and hence is capable of minimizing vibration throughout the entire plate. Within the control framework, two cases were considered here; the case when the prior knowledge of the incoming disturbance in terms of reference signal is vailable and the case when it is not available. For the case when the reference signal is available, spatial feedforward controller was designed; whereas for the case when the reference signal is not available, spatial feedback controller was designed to attenuate the global disturbance. The effectiveness of spatial controllers was then compared with that of the standard point-wise controllers numerically and experimentally. The experimental results were found to reflect the numerical results, and the results demonstrated that spatial controllers are able to reduce the energy transfer from the disturbance to the structural output across the plate in a more uniform way than the point-wise controllers. The research work has demonstrated that spatial controller managed to minimize the global plate vibrations and noise radiation that were due to the first five modes. / Thesis (M.Eng.Sc.)--School of Mechanical Engineering, 2005.

Masters Research - Master of Philosophy (MPhil) / The growing need of creating a network of sensors in critical environment to monitor, sense and alert an operator about the environment gives rise to the research work carried out in the area of power supply to these sensors. Wireless sensors are usually designed to run on batteries. However, as the number of sensors increases and the devices decrease in size, there is clearly a need to explore alternatives to battery power for wireless sensors. Reliable, efficient and environmentally friendly energy harvesting methods could be adopted to design and build a new electronic device that could be used to replace or supplement batteries in wireless sensors. This thesis focuses on potential ambient sources of power that can be harvested to run low power wireless sensors in mining environments. It discusses several techniques for converting energy from such sources into useful electrical power. In particular, piezoelectric power conversion technique is described in detail. Drilling is a crucial component in both underground and surface mining. Water jet assisted drilling is an example of a new drilling technology employing wireless sensors. There are various forms of energy that could potentially be used to power wireless electronic sensors provided the waste energy can be tapped in an intrinsically safe way. In this particular project, the required power to run sensors could be generated by converting mechanical vibration produced from water jet assisted drilling into electrical energy with an intrinsically safe circuit. Various power scavenging methods were researched, but vibration-to-electricity conversion using piezo-ceramic material was selected as the most promising method for this project. Piezo-based energy conversion is not normally good for mining applications because of intrinsic safety issues. In the case of water jet assisted drilling, however, the environment is much more suitable for piezo-electric conversion. A detailed computer model for this type of power conversion has been developed. The mechanical model of the vibration spectrum is based on test data from the Contents 2 CRC-Mining group. A power conversion circuit has been built, detailed circuit simulations studied and the experimental results are demonstrated. An example vibration scenario consisting of (20x10^-6)rms strain is considered. Based on this, and a detailed model of a 70mmx25mm PZT piezoelectric patch with 0:2mm thickness, our computer simulation studies and experiments demonstrate the ability to harvest up to 210mW of power.

Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 99-101). Also available in electronic format on the Internet.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vi, 70 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 67-70).

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Dissertation (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Dissertation (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Thèse (M.Eng.) -- Université du Québec à Chicoutimi, 2007. / La p. de t. porte en outre: Mémoire présenté à l'Université du Québec à Chicoutimi comme exigence partielle de la maîtrise en ingénierie. CaQQUQ Bibliogr.: f. 133-137. Document électronique également accessible en format PDF. CaQQUQ

Thesis (Ph. D.)--University of Canterbury, 2008. / Typescript (photocopy). "November 2008." Includes bibliographical references (p. [144]-149). Also available via the World Wide Web.

Thesis (Ph.D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Speyer, Robert; Committee Member: Gerhardt, Rosario; Committee Member: Liu, Meilin; Committee Member: Lynch, Christopher; Committee Member: Wilkinson, Angus