Example solution
Problem 10. Consider the fillet welded cruciform weld show with t1 = t2 = a = g = 12 mm. According to Radaj and Zhang, the notch stress concentration factor for this weld, is 1.192 ∗
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a) Use the effective notch method to estimate the fatigue life of this component.
b) The cost of the weld can be reduced by reducing the throat thickness, a. What throat
thickness should be used if the required fatigue life is 1 000 000 cycles?
a) To solve, one should notice that a/t1 = t2/t1 = g/t1=1 . The effective notch methods uses =1
.
therefore 1.192 ∗ 1 12
3.16
2 10 ∗ 225
Using the effective notch method, fatigue capacity Fatigue life estimate is ∆ ∗
2.28 10
b) For the required life of 1 000 000 cycles, 2.28 10
1000000
2.83 1
100 ∗ 3.16
∆ ∗
2.28 10 722000
1
100 ∗
2.83
3.16 ∗
.
which when solved for a gives a=17 mm.