Hulls (Naval architecture)

This research used Electrochemical Impedance Spectroscopy (EIS) as a non-destructive technique to evaluate coating performance and determine the electrochemical characteristics of Special Hull Treatments (SHT). The evaluation of the SHT system provided information on its corrosion resistance and cathodic protection-influencing characteristics. The coating's impedance was analyzed while exposed to ambient versus 4.5 MPa pressures and immersion times of 1 to 9 days in seawater. Eleven specimen types were evaluated based on coating seam orientation and composition. The data support the conclusion that there was no effect on impedance values and phase shifts due to orientation, formulation, pressure values or immersion time. However, temperature increase above 30° was shown to decrease the impedance values of the SHT specimens.

In the present dissertation, the hydrodynamic and hydro-elastic characteristics of ship hull and plate vibrations are analyzed using theoretical and numerical methods. The wave forces are determined using a suite of methods which include the Froude-Krylov method for incident wave forces, Wagner's method and ABS rules for the slamming wave force, and numerical methods for nonlinear wave radiation forces. Finite difference methods are developed to determine the wave forced vibrations of ship hull plates which are modeled using a range of plate theories including nonlinear plate theory with and without material damping and orthotropic plate theory for stiffened hull plates. For small amplitude deformation of thin plates, a semi-theoretical superposition method is used to determine the free and forced vibrations. The transient ship hull vibration due to whipping is also analyzed using the finite difference method. Results, in the form of deformations and stress distributions, are obtained for a range of scantling and wave parameters to identify key parameters to consider in ship structural design.