N-SIF based fatigue assessment of hopper knuckle details

A somewhat innovative fatigue assessment approach is applied to a typical shipbuilding structural detail: the hopper knuckle. This detail was benchmarked in the Technical Committee III. 2 report (Fatigue & Fracture) of the last ISSC 2009 Congress and significant scatter among results obtained by various fatigue assessment procedures was found, even when considering specific corrections of the commonly applied approaches for such type of welded joints. This paper aims at providing verification of a Notch Stress Intensity Factor (N-SIF) based approach in a case currently of concern within the shipping community, namely the Strain Energy Density (SED) approach, that is a promising method for fatigue assessment of welded structural components proposed in open literature. Comparisons with experimental and numerical available results are provided with results obtained applying other approaches, highlighting advantages and disadvantages of the SED approach in the captioned case.