Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--Ohio State University, 1957. / Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 123-130). Available also in a digital version from Dissertation Abstracts.

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This thesis presents the results of an investigation into the application of statistical energy analysis (SEA) to predict structure-borne noise transmission in ship structures. The first three chapters introduce the problems of noise and vibration in ships; the previous research on the application of SEA to ships; the basic theory of SEA and the experimental measurement techniques and procedures used to gather data The main body of this thesis presents a wave transmission model for the hull frame joint which is commonly encountered on the hull, bulkheads and deck plates of ship structures. The wave model allows the transmission coefficients to be calculated for hull frame joints which can be used in the coupling loss factor equations of SEA models. The joint model has been verified against measured data taken on a simple two subsystem single joint laboratory structures and a large complex 38 plate test structure with multiple joints intended to represent a 1/10' scale model of a hull section. In addition to the laboratory structures, the SEA modelling of sections of a ship is presented for a large ribbed deck plate, a section of the ship superstructure and a section of the ships hull. The results from the SEA models are compared with measured attenuation data taken on the respective ship sections. A large amount of damping data has been gathered on the test and ship structures and an equation for the internal steel based on data gathered by other researchers has been verified. It has been shown in this thesis that SEA can be applied to ships. Better agreement is found with real structures in contrast to the poor results presented for SEA when applied to simple one dimensional structures. The level of detail of the model is important as a coarse model yields better predictions of vibration level. As with all models the results are sensitive to the damping level and it is necessary to include bending, longitudinal and transverse wave types in any SEA model to obtain the best prediction. It was also found that the flange plates can be neglected from the frame joint model without compromising the accuracy.

This thesis investigates the problems of applying Statistical Energy Analysis (SEA) tomodels that include solid volumes. Three wave types (Rayleigh waves, Pressure wavesand Shear waves) are important to SEA and the mathematics behind them is explainedhere. The transmission coefficients between the wave types are needed for energytransfer in SEA analysis and different approaches to solving the properties of wavepropagation on a solid volume are discussed. For one of the propagation problems, asolution, found in Momoi [6] is discussed, while the other problem remains unsolveddue to the analytical difficulties involved.

a b s t r a c t A study concerning the propagation of free non-axisymmetric waves in a homogeneous piezoelectric cylinder of transversely isotropic material with axial polarization is carried out on the basis of the linear theory of elasticity and linear electro-mechanical coupling. The solution of the three dimensional equations of motion and quasi-electrostatic equation is given in terms of seven mechanical and three electric potentials. The characteristic equations are obtained by the application of the mechanical and two types of electric boundary conditions at the surface of the piezoelectric cylinder. A novel method of displaying dispersion curves is described in the paper and the resulting dispersion curves are presented for propagating and evanescent waves for PZT-4 and PZT-7A piezoelectric ceramics for circumferential wave numbers m = 1, 2, and 3. It is observed that the dispersion curves are sensitive to the type of the imposed boundary conditions as well as to the measure of the electro-mechanical coupling of the material.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

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