- #1

MysticDream

- 97

- 8

- TL;DR Summary
- Trying to estimate the fatigue limit for very low stress.

I’m wanting to estimate the fatigue limit for copper piping that has a factor of safety of about 5 (yield FOS). All I can find online is graphs of curves that go to about 100 million cycles, but I need more. Obviously for these materials that don’t have a distinct fatigue limit like steel, the slope of the curve goes more horizontal as stress levels decrease, but I want to know what the slope is up to a billion cycles if possible. This piping will be subjected to external gas pressure cycles of 300 cycles per min, 24/7. That means after one year, it will have gone through about 157,680,000 cycles. I need to have a reasonable estimate of how long these would be in service before they fail from fatigue. If anyone has any insight into this, I’d greatly appreciate any assistance.