ABSTRACT
Fatigue is often the governing phenomenon in the design of welded joints in highly dynamic environments. The fatigue damage of welded joints can be found using the S-N curve approach in combination with the stress ranges calculated by finite element analysis. However, predicted fatigue lives are highly uncertain due to uncertainties originating from the S-N curves, material and geometric properties and the FE models used. The stochastic finite element method is one method that can be used to include spatial randomness in welded structures. In this paper, the stochastic finite element method is used to investigate the random response of a beam for fatigue analysis based on the Karhunen-Loéve expansion. The beam simulates a member in an offshore jacket structure. The random stresses are determined and used for a subsequent fatigue analysis of the weld. The results show that the fatigue life is highly influenced by the stochastic variance of the bending rigidity.
