Fatigue curve for bolting
Fatigue curve for bolting
(OP)
I have an application in which the fatigue cycle numbers exceeds the ASEM VIII-2 FIG 5-120, which only has maximum cycle number of 1 million. Our cycle numbers is in the range of 10 million. How should I deal with this case?
Thanks in advance.
Henry
Thanks in advance.
Henry





RE: Fatigue curve for bolting
RE: Fatigue curve for bolting
I noted. Now the question is: the 5-110 curve only applies to UTS<100 ksi as per 5-120(a); if I use 5-110 curve, should I assume that the high strength materials have a UTS of only 100ksi despite the fact that they (eg B7, L7) have higher strength?
Thx, Henry
RE: Fatigue curve for bolting
See paragraph (b).
RE: Fatigue curve for bolting
By checking these two curves, at 1 million, 5-110.1.1 gives a Sa of 20 ksi and 5-120.1 gives Sa of 15 ksi. I do not quite understand that 5-110 allows a higher Sa than 5-120. Would you please give me some clues?
Thanks again!
RE: Fatigue curve for bolting
Your interpretation of (b) is not totally correct. You can use the method in 5-110. However, paragraph (b) the way I understand it still requires the use of Figure 5-120.1