You define a variable-amplitude fatigue loading event based on the static study you performed earlier on the model.
- In the Fatigue_study tree, right-click Loading (-Variable Amplitude-)
and select Add Event 
.
-
In the PropertyManager, under Load, click Get Curve.
- In the Load History Curve dialog box, click Get curve.
-
Browse to the installation folder of the Function Curve Library
(*.cwcur) named sample sae curves.cwcur.
See
for the installation location of the Function Curve
Library.
-
In the Function Curves
dialog box, under Load History Curve,
select SAE Suspension, and click
OK.
The curve is loaded.
The first
amplitude of the curve is -999 and the mean is negative. The Gerber method
will be used to account for the mean stress correction as specified in the
properties of the study.
- In the Load History Curve dialog box, click OK.
The first amplitude in the time history is -999. Suppose that this value corresponds to a total bearing load of 12,000 lbs (twice the total bearing load applied in the static study). The scale factor (SF) in the next step should be calculated as: SF = (12000/6000)(1/-999)=-0.0020
- In the Add Event (Variable) PropertyManager under Study, select the Ready_Static and set the Scale associated with the static study to -0.002.
The program scales the stresses in the same way. For example, the maximum von Mises stress associated with fatigue loading amplitude A is equal to (-0.002)(A)(S), where S is the stress associated with the static study at a location.
- Under Option, set Number of repeats to 1.
-
Click
.