No of cycles in a sine test
No of cycles in a sine test
(OP)
I wonder: How many cycles are accumulated in a sine test? If we are sweeping through frequencies and we are hitting some natural frequencies in the process, will the number of (fatigue) cycles be the fn*60 cycles pr minute? Since the time at peak stress will be rather short, will that be real fatigue cycles, or should we count cycles within the rms stress range. sqrt(2)/fn-sqrt(2)*fn. The latmter will be more cycles at lower stress level. Anyone with any experience here? We ar sweeping at 2 Oct/min.
Appreciate any input from experienced test engineers.
Appreciate any input from experienced test engineers.





RE: No of cycles in a sine test
Jim
Jim Kinney
Kennedy Space Center, FL
RE: No of cycles in a sine test
RE: No of cycles in a sine test
Usually our loads are low enough that we don't worry about fatigue, but we have to check the box that we looked at it.
If it were critical, then you are correct about counting around peak responses. Search rainflow counting for another method.
Jim
Jim Kinney
Kennedy Space Center, FL
RE: No of cycles in a sine test