| The fatigue collapse is an important failure mode, especially for ocean-platform structure. There are many stochastic factors affecting their design. It includes material properties and dimensions, uncertain loads, calculation models and so on. So it is necessary that structures should be evaluated by reliability methods. Because of the progressive fatigue of elements, the reliability of structure will reduce as it is going. If the real reliability is less than regulated value, the structure is dangerous, So we should inspect them . If cracks are found, some repairs should be done. The updating reliability is derived on the basis of inspection and repairs. Main content of this thesis is as following:1. Using S-N model, studies have been carried out on the structural collapse due to progressive fatigue failure of joints. The first order reliability method is used for evaluating the fatigue failure probability of two systems. The paper make use of Branding and Bounding Method to derive the main failure modes.2. The inspection is proposed in the paper. Inspection is a new topic , it have a certain of practical value. TLP have some advantages in the respect of exploring the oil field. The studies which have been carried out on the TLP in this paper have some important meanings.3. Monte Carlo method is used to calculate a function which is a formulation about a number of joints.
|
PDF Full Text Request