PSI - Issue 57

7

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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

475

As expected, and as evident by Figure 5, the weld toe notch is the most critical area of fatigue failure. Due to the presence of stress concentrations at the weld notch, the weld toe is the most likely area of failure, and hence governs the fatigue life of the welded structure. Therefore, modifying the weld toe region using the HFMI treatment has a significant effect on the fatigue life of the structure, and hence is beneficial in extending the fatigue life of the structure (Marquis and Barsoum 2016). In the units of years, for an applied stress of 100 MPa, the HFMI treated sample shows a fatigue life increases by a factor of 3.7-6.5 while the fatigue life increases by a factor of 1.1-2.3 is seen for an applied stress of 150 MPa (Table 5 ).

Figure 5: Stress Contours, 100 MPa Applied stress, 12 mm thickness.

Table 5: Evaluated fatigue life (weld length: 500 mm)

6mm (lifetime in years)

12mm (lifetime in years)

Applied Stress

AW

HFMI treated

AW

HFMI Treated

100 MPa 150 MPa

98

738

49

232 30.6

29.1

97

14.5

The production cost was calculated as a function of the weld length for the 6mm cruciform weld sample, assuming a production demand of 85000 parts per year (PPY). Figure 6 shows a significant influence of the welding length on the production costs of the welded sample. Additionally, the production cost vs production volume curve also shows a step-wise behavior due to the dependency of the capital costs on the production volume and the number of production lines. Moreover, there is a clear difference between the production costs of the as-welded sample vs the HFMI treated sample. Therefore, it is evident the added automated post-weld treatment adversely affects the production costs of the welded structure.