Fatigue is an important character for the flexible pipes as they are always exposed to dynamic loading. For nonbonded flexible pipes, fatigue and stress analysis can be performed based on different assumptions of slip behaviour. Different slip assumptions used in estimating the slip stress always play a determinative role in the prediction of fatigue damage. Thus, this thesis will focus on the study of the slip behaviour between tensile armour layers of nonbonded flexible pipes. The results can be used to support the basic assumptions for further fatigue analysis. The main object of this thesis is to summarize the existing analytical methods for stress and slip analysis of nonbonded flexible pipe armouring layers and to verify that the improved finite element models can give adequate description of the flexible pipe slip behaviour.In previous version of BFLEX, the transverse slip effect for nonbonded flexible pipes has been neglected. In this thesis, transverse slip regime has been activated in the updated BFLEX by developing a new type of beam element hshear353 and a new type of contact element hcont453. Finite element models use these two elements have been made and several case studies have been carried out.For axisymmetric loading, two analytical solutions, one obtained from the equations by Witz&Tan[13], one from Sævik[2] have been compared with the result from numerical simulation. It has been found that Sævik’s solution matches better with the BFLEX solution comparing to Witz&Tan’s solution. For flexible pipes exposed to bending, influences on slip behaviour from several pipe parameters, namely friction coefficient, axial strain and global pipe curvature, have been investigated. The numerical results are also compared with analytical solutions obtained from Sævik[2]. It has been found that the numerical solutions can give excellent agreement with analytical solutions. It is further concluded that the outer tensile armour layer do not influence much on the inner layer slip behaviour.In addition, the cyclic bending effects on nonbonded flexible pipes have been investigated. It has been found that the tendon behaves differently from case to case. The inner and outer layers behave differently. Only a few cases have been studied for this problem due to time limitation. The overall conclusion is that the developed BFLEX model is capable of describing the stresses and local displacements of flexible pipe for simple cases. The developed numerical model can further be used in the study of fatigue in flexible risers. However, more studies on influence from multi-tensile layers and cyclic bending are needed in the future.

Internal combustion engines have been very successful as power producers in the marineapplicaiton due to their simplicity of construction, high efficiency and long track of proven technology. However, as the environmental foot print of industry is gaining more and more attention, the emission from the engine must be reduced. The main emission fromthe diesel engines are namely nitrogen oxide(NOx) and particulate matter(PM). Sulfuroxide(SOx) and carbon dioxide emission(CO2). In the marine industry, the transientemission has not been brought to the table of discussion when it comes down to theregulations. However, the assessment and improvement in the transient emission willgain more attention.In order to predict the emission from the diesel engine in the generic manner, the dynamic engine model should be developed. This model must be able to capture the in-cylinder process during the combustion in cylcle-to-cycle resolution. Transient load would put more challenges to the prediction as the in-cylinder states are far from the steady-state conditions. In the thesis, the dynamic simulation model of the diesel engine is developed in order to predict the emission. Firstly, the emission from the diesel engine, with special focus on NOx formation, is reviewed in general. Then overall process of the development of the mathmatical model of the diesel engine is described. Bond graph model was used as the framework of modeling approach. Finally the simulation result is compared with the test result from the laboratory and recommendations for further development are presented.The main contributions of the thesis are:• A overall process of building the engine model of was reviewed and implemented. It covers most of the building blocks from the thermodynamic calculation to the calculation of states of the components of the diesel engine.• The model developed in the project has significant improvement in terms of computational efficiency. Implementing Grill’s method for the calculation of the equilibrium composition of the combustion gas was the key to this success.• The bond graph model based on the multi-component gases in the combustion gases was constructed and it founded a ground for adaptation of the emission reduction strategy such as exhaust gas recirculation.• The overall model was built with component libraries which can be reused in the future project. Full description of the components libraries is given so that potential users may have the easy access.• A mathmatical model for NOx is coupled with the dynamic engine model together with the two-zone model approach. The calculation of the two-zone model in the absence of the pressure profile was achieved with an effective method so that calculation time has not increased significantly from the single zone model.

Texte remanié de: PhD thesis--University of Southampton, 1997. / Bibliogr. p. 104-113.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 192-206).

Thesis (M.M.S.)--Memorial University of Newfoundland, 2000. / Bibliography: p. 58-59.

Thesis (M. Arch.)--University of Hong Kong, 1999. / Includes special report study entitled: Aquaculture : architecture along the sea's edge. Includes bibliographical references.

Thesis (M. Arch.)--University of Hong Kong, 2002. / Includes special report study entitled: Urban waterfront and space. Includes bibliographical references.

Thesis (M.A.S.)--Memorial University of Newfoundland, 2002. / Bibliography: leaves 56-57.

Thesis (M. Arch.)--University of Hong Kong, 1999. / Includes special report study entitled: Methods of offshore construction. Includes bibliographical references.

Thesis (M.S.) in Oceanography--University of Maine, 2002. / Includes vita. Bibliography: leaves 72-78.