PSI - Issue 57

Kashif Kamran Toor et al. / Procedia Structural Integrity 57 (2024) 772–784 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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For details where the hot spot stress method is not applicable the effective notch stress method is recommended. Effective notch stress: Fatigue stress can be calculated directly at the notch radius if a detailed model including a fictious weld toe radius equal to 1.0 mm is included in the FE analysis. This method will be used as benchmark in this study for comparison of hot spot stress methods. The selected hot spot is categorized as type ‘b’ hot spot and is a ssessed using a detailed FE model. The cope hole and attached hot spot is shown in Fig. 5.

Fig. 5. Hot spot location.

2.4. INF Generation The INFs were generated using a conventional approach by applying the unit load in 6 DOF’s at each cut boundary section of the joint. The cut boundary section is the location of the joint elements’ interface in the global model where the actual load response is used to calculate the structural hot spot stress in relation to the INF. Only the stress normal to weld toe, SX, was used as read out stress and the hot spot stress was calculated based on the extrapolation method type ‘b’ . The FE model was fixed in all DOF at the leg side and solutions were obtained for unit load application in each of 6 DOF at each free cut boundary location. Unit force and moment of 1 MN and 1 MNm was applied respectively. For the selected hot spot INF are generated for 30 load cases representing the hot spot stress per unit load applied in 6 degrees of freedom (DOF) for each free cut boundary in the FE model. The cut boundary locations and local coordinates for the selected joint are shown in Fig. 6.

a

b