To create a new SN curve:
- In a Fatigue study, add a fatigue event.
- In the Material dialog, on the Fatigue SN Curves tab, in the Source box do the following:
- For Interpolate, set the scheme for interpolating alternating stresses against the number of cycles of S-N curve.
- Select Define and select a curve from the ten curves that appear in the menu.
- In the Table data box, do the following:
- In the Stress ratio (R) box, enter the stress ratio associated with the curve.
R = Smin/Smax
where:
Smin is the minimum stress in the stress cycle and Smax is the maximum stress.
and,
Smean=(Smax + Smin)/2
where:
Smean is the mean stress in the stress cycle.
- Set the unit of stress.
- Populate the curve data by entering Alternating Stress values versus number of Cycles, or click File to import a Curve Data Points File (*.dat).
To add a new row, double-click in cell under the Points column.
The format of the Curve Data Points File (*.dat) should have two columns: Number of Cycles (first column) and Alternating Stress (second column).
- Click View to graph the data or Save to save the curve to a library.
Preview box shows the curve as it is defined.
- To delete a row, highlight it and click the Delete key or right-click it and select Delete.
- Type a source of reference for the SN curve data in Source.
The format of the Curve Data Points File (*.dat) should have two columns: Number of Cycles (first column) and Alternating Stress (second column).
- Click Apply.