Fatigue sensor

The Fatigue sensor can be added by right-clicking on the desired element and toggle the sensor on, as shown in the picture below:



The Fatigue sensor provides the following fields:

FieldUnitDescription
Stress pt xMPaThe stress of the element, see below for point description
Peaks and Vallies pt xMPaThe list of peaks and vallies (i.e. extrema) for the stress point x time series
Ranges pt xMPaThe ranges of the peaks and vallies list
Damage (w/o uncounted) pt xThe damage at point x if uncounted half cycles are not onsidered
Fatigue life (w/o uncounted) pt xyearThe fatigue life at point x if uncounted half cycles are not considered
Damage pt xThe damage at point x
Fatigue life pt xyearThe fatigue life at point x
Uncounted half cycles count pt xThe number of half cycles that have not yet been counted in the Rainflow counting algorithm

The position of the point is given in degrees from the 1st principal axis of the element and with a positive angle being towards the 2nd principal axis (see section 3. Element coordinate system of the Coordinate systems document).


Note: you can specify the number of points within a cross section where stresses will be computed in two ways:
  • in the Fatigue section of the Preferences. Points will always be evenly distributed accross the cross section, with one point at 0 degrees.
  • in the Support section files defining the support section 


Note: the Peaks and Vallies and Ranges fields are not time series. They produce a list of extreme that can be viewed when exporting the sensor.


1 Modifying the S-N curve for a fatigue sensor

When adding a fatigue sensor, the S-N curve used to compute the fatigue characteristics will be the default one, specified in the Fatigue tab of the Preferences.

It is also possible to modify the S-N curve of a sensor once the sensors has been added: you can either double-click the name of the sensor, or right-click the name of the sensor and select options, as illustrated in the figure below:



This will open the Customize sensor window where you can change the name of the Sensor and select the S-N curve that will be used to compute the fatigue characteristics. This window is shown in the figure below.




Note: the fatigue options shown in the Customize sensor window do not necessarily correspond to the options that have been applied to the sensor. The goal of this window is to select an S-N curve, rather that provide information about the current S-N curve