PSI - Issue 57

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Kaushik Iyer et al. / Procedia Structural Integrity 57 (2024) 469–477 Kaushik Iyer, et.al. / Structural Integrity Procedia 00 (2019) 000 – 000

Figure 6: Variation of production cost wrt (a) Weld length (b) Production volume

As evident by Table 5, the HFMI treatment significantly increases the useful fatigue life of the structure. Therefore, under the applied loading conditions, there is a lesser probability of the HFMI treated welded structure to experience failure. However, the useful life of the as-welded specimen under the applied load of 150 MPa is 29.1 and 14.5 for 6mm and 12mm plate thickness respectively. Due to the fatigue life being lower than the design life of 20 years, there is a need to implement repair mechanisms, thus further increasing the accumulated life-cycle costs. However, when the welded sample is treated with the HFMI treatment, the need for such a repair is no longer present due to the relatively longer fatigue life. Moreover, with increasing loads, the HFMI treatment can play a role in increasing the repair interval, thus significantly reducing the life-cycle cost of the weld. 5. Conclusions In this study, the life-cycle cost of welded structures was evaluated using an activity-based costing model. In order to assess the economic viability of post weld treatments, the life-cycle cost of a welded structure treated with an Automated HFMI treatment was compared with the cost of an as welded structure; special attention was paid in assessing the production costs of the automated HFMI treatment. Furthermore, the influence of weld geometry on the life-cycle costs was assessed by varying the plate thicknesses and the weld length. Moreover, the fatigue life of the welded structure, as calculated using the effective notch stress method, is used for calculating the cost impact in the use-phase. The results show a significant influence of the welding length on the production costs of the welded sample. Moreover, there is a clear difference between the production costs of the as-welded sample vs the HFMI treated sample. Therefore, it is evident that the added automated post-weld treatment adversely affects the production