The new IIW recommendations for fatigue assessment of welded joints and components – A comprehensive code recently updated

The recommendations of the International Institute of Welding (IIW) on fatigue of welded components and structures and on the effect of weld imperfections in respect to fatigue have been published firstly in 1996. It was published in English, German, Japanese and French. A comprehensive code was established, which covered all current methods of verification, as e.g. component testing, nominal stress, structural stress, notch stress method as well as fracture mechanics assessment procedures. Detailed guidance for assessment of weld imperfections is also given. The safety philosophy covers the different strategies, which are used in various fields of application and gives a specified choice for the designer. The update of the recommendations was finalized in 2006. The main areas of update are the structural hot-spot stress concept, which allows now for an economic and coarser meshing in finite element analysis, the extension of the effective notch stress concept to welded aluminium structures and the numerical assessment of post weld treatments for improving the fatigue properties. It is expected that the new update will exert the same impact on design and codes as the old one.