This thesis investigates the progressive collapse behaviour of lightweight ship hull girders including the effects of compartment level buckling modes. An extension to the progressive collapse methodology is proposed, which has capabilities to predict the compartment strength of a lightweight aluminium midship section. Nonlinear finite element analysis is used to validate both the progressive collapse methodology and the analytical approach proposed for determining the buckling capacity of orthogonally stiffened substructures within the hill girder compartment. The research has been undertaken due to the continued growth in the size of large lightweight craft in both commercial and naval vessels, combined with increasing operability requirements for these vessels. The development of large and lightweight marine structures, predominantly built from aluminium alloy, has raised important issues regarding the response of the hull girder under primary hull girder bending.

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In this research, the Computational Fluid Dynamics (CFD) approach, based on the solution of the Reynolds Averaged Navier-Stokes (RANS) equations is used to study the classical ship hydrodynamic problems, all being affected markedly by the presence of free-surface, namely: ship resistance, propulsion, manoeuvring, seakeeping and stability, the latter focusing on flooding of a damaged ship. In this respect, this thesis represents a marked deviation from classical approaches and a unique contribution to ship dynamics and hydrodynamics. The RANS equations with SST K-w two-equation turbulence model and Volume Of Fluid (VOF) formulation were discretised by the finite volume (FV) method and the pressure-coupled governing equations were solved by the SIMPLE algorithm. The geometric reconstruction algorithm was adopted to locate transient free surfaces. The second order upwinding scheme was used for the discretisation of the convection flux and Multi-grid Acceleration was applied to improve convergence. In addressing ship resistance, grid sensitivity studies were carried out according to the “ITTC guideline of quality” manual. The computed results were verified and validated against available model test data. Additionally, the results of the effects of the turbulence models were investigated by comparing turbulence quantities predicted by SST K-w and RSM. In addressing ship propulsion, the propeller was modelled as an actuator disk of equivalent thrust and torque. Distributions of the body force were compared with results from a parametric study and the implementation of the body force approach was validated by model test data. In addressing ship manoeuvring, numerical PMM simulations of pure sway and yaw motions were performed. The numerical results were benchmarked against physical experiments. The computed hydrodynamic derivatives were compared with empirical formulae and subsequently implemented in manoeuvring simulations. In addressing seakeeping, incident waves were generated by a numerical wave maker and the computed results for wave diffraction were validated against physical measurements. Furthermore, RANS simulation for roll decay was undertaken and validated against results from model tests. Finally, a numerical roll tank was established to study the hydrodynamic coefficients of the roll motion in intact and damaged conditions and the corresponding results were compared with available model test data. In conclusion, systematic studies and ensuing results from numerical simulations of classical ship hydrodynamic problems using RANS demonstrated beyond doubt that CFD could and should play an important role in the design, analysis and evaluation of ship hydrodynamic performance. In addition, they provide unshakeable evidence of the level of capability to make the next important step: rendering CFD a routine "tool" in ship dynamics and hydrodynamics.

The structural systems in practice are often very complex consisting of iber of components having intricate geometries. Each component may have different failure modes which depend upon variability of material properties, production processes and loadings. Optimisation on design requirements of the complex structural system requires adopting modern computer techniques for evolution and analysis. Finite Element Methods (FEM) is widely used computing technique in engineering design. Since structural analysis tools, such as Finite Element Analysis (FEA) software, are traditionally developed independent of reliability technologies. Consequently, it is common and conventional approach to perform structural analysis and reliability analysis separately, mainly, because established methods and tools for combined analysis are not readily available as yet. Each of the technology domain viz. structural analysis and reliability analysis, however, have established state of the art tools which are under evolution for integrated and combined application in structures reliability analysis and design. These studies shall encompass review of the various available methods & tools for reliability analysis and integration of these techniques to Finite Element Methods to fully utilize the state of art development in the fields of structural analysis and reliability analysis.

On December 17th 2002 the World Meteorological Organization issued a statement according to which the global mean surface temperature has risen and consequently 2002 was the warmest year in the 1961-2002 period.  Positive sea surface temperature anomalies across much of the land and sea surface of the globe in general contributed to the near record temperature ranking for the year along with climate anomalies in many regions across the globe.  Climate change as a result of global warming is a worldwide occurring phenomenon which the experts have only recently started to understand and which affects and significantly will affect us in the near future.  The effects of climate change have been somehow neglected by the ship and offshore related academic and research communities. In the case of thermal effects on ships structures, unless the problem solved is temperature dependent, this type of stress has often been neglected and not been taken into account in most types of analysis.  The most likely reason behind this would seem to be that the stresses produced from temperature changes would be too small to be taken into account compared with still water loads or wave bending stresses.  This is not the case though.  Records exist of ships having broken in half while moored in still water and major hull factures occurred in still water while the temperature was changing as it can be seen from the relevant published literature.  Very little work on thermal stress on ship structures has been published since the 1950s and 1960s and no work has been done that considers temperature effects on ultimate strength. Research undertaken aims to incorporate temperature effects on existing ultimate strength formulation by using a thermal stress approach, compare and use recently proposed corrosion models to model corrosion effects on ultimate strength and provide a foundation on which reliability analysis could then be performed for Tanker/FPSO structures operating in the North Sea.  After comparing a number of possible approaches that would enable to loading components to be combined in a stochastic fashion, the loading part of the reliability analysis is handled using extreme wave statistics and the Ferry Borges-Castanheta load combination method. Annual reliability indices and probabilities of failure are calculated for hogging and sagging conditions using both time-variant and time-invariant approaches and a variety of reliability analysis approaches showing the effects of temperature along with partial Safety Factors for all variables taken into account.