Laminated composite plates have become an important and proven structural material in aerospace and ocean vehicles. However, because of the inherent orthotropy of laminated composite materials the analysis of these structures is complex and usually cannot be adequately performed using classical methods. In this dissertation the formulation of the fully coupled fluid-structure interaction of a laminated composite plate and its surrounding fluid medium is presented. The solution technique involves the finite element method for modeling the structural response and the boundary element method for modeling the acoustic field. The model incorporates the Mindlin plate theory which includes five degrees of freedom. An improved integration technique is demonstrated which significantly reduces the approximation error. Storage requirements are reduced by grouping complex numbers. Finally the fully coupled fluid-structure interaction involving laminated composite plates is modeled using the combined FEM-BEM approach demonstrating the usefulness and the significance of the method. / Ph. D.

A variation of the boundary element method is developed to determine the distribution of frictional heat and the ensuing surface or subsurface temperature rise caused by frictional heating between sliding solids. The theoretical model consists of two semi-infinite substrates each coated with a film of arbitrary thickness and thermal properties. A three dimensional transient analysis is developed which involves the thermal coupling of the two sliding solids at the true contact areas. The boundary element solution is based on a moving Green's function which naturally incorporates the combined conduction and convection effects due to sliding. Results are presented to display some of the important numerical characteristics of the boundary element solution method. Results are also presented that show the sensitivity of surface temperature rise to contact area evolvement, geometry and subdivision. The effects of surface film thickness and thermal properties on surface temperature rise are presented for a range of Peelet numbers. Lastly, a comparison of theoretical predictions and experimental measurements for surface temperature rise of a graphite epoxy ball loaded against a rotating sapphire disk is presented. / Master of Science