Low-Cycle Fatigue
Low-Cycle Fatigue
(OP)
If I have a rectangular sheet of gauge 12 steel (33 Fy, 45 Fu, 30% elongation), is there an easy way to estimate how many times that I can bend the sheet back and forth (holding the lower half in a vise and bending the upper half back and forth in 180 deg. cycles) before it starts to crack? Is there some sort of low-cycle fatigue equation that I can use to estimate this value.
Thanks,
J
Thanks,
J





RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
If the bending is exceeding the yield strength each time, is this still considered fatigue?
Nick
I love science!
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
One might also argue that Mean - 2 Standard Deviations is not a very good design limit for low-cycle fatigue since over 2% could be expected to fall with fewer cycles, but that really was not part of the OP.
As a rule, though, I'd trust the answer using davefitz's method more than any calculated value.
rp
RE: Low-Cycle Fatigue
RE: Low-Cycle Fatigue
So in low cycle fatigue you add the typical fatigue damage to work hardening beyond elastic limit and to residual stress effects.
Hope it helps.
Stefano