SN Curve

SN curves are specified and used in combination with the fatigue analysis.

Specifying the SN curve by selecting:

  • Fatigue limit indicator, options:

    • No fatigue limit

    • Fatigue limit give by stress cycles

    • Fatigue limit give by stress ranges

A SN curve can be specified either

  • choosing the predefined SN curves in the drop down list

  • manually specifying the fatigue limit, reference thickness, thickness correction exponent, the slope m and the constant \(log_{C}\) of the first segment of the curve. Additional segment can be defined by adding slopes and transition points.

The unit of fatigue limit is dependent on the choice of Fatigue limit indicator
If a fatigue limit is specified, stress cycles outside the remaining range will not contribute to the fatigue damage.
SNcurve
Figure 1. Example: SN curve with two segments and fatigue limit