Rainflow Fatigue Damage Calculation
Hi
Was there any further update to the forum post below?
I am experiencing similar issues. As a test setup I have strain gauged a tuning fork and analysed two loading scenarios, one that is repeatably loading the fork at its natural frequency so the cycles are high and the load range changes over time due to the damping and the other is manually bending the forks. Which produces much less cycles but higher stress ranges.
Like the previous post the Damage value that is calculated vs the dewesoft value are very different. I have attached a number of files below outlining the issue. Is it possible to extract the actual values etc and the equation that is used for the damage calculation within the module.
Attached files:
In the training documentation the SN curve is defined as the stress range from EN 1993-1-9. I'm using a very similar curve from DNV CP203 (base material not weld detail). However, whenever the stress is defined as the stress amplitude (Stress range / 2) and not the stress range, the results appear much closer to the hand calculation.
Another example
Is this just a coincidence or should the stress be defined as the amplitude?
NVH Application Engineer
Dear Mr. Smyth,
in the previous version the SN curve needs to be defined in Amplitude. In the newer version (SP12) you can select in SN curve editor, if you want to define your SN curve in Amplitude or Range.
Best regards,
Hi Jernej
Thanks for your response - I updated to SP12 and can confirm that everything is working great. Obviously the values are highly dependant on the bin width etc.
Thanks.