I have just written a post in my blog regarding the new release of winLIFE 4.0, a fatigue analysis software integrated with FEMAP that take advanced of NX NASTRAN results (as well as from others FEM/FEA codes) to perform Fatigue Analysis, both uniaxial & multiaxial. The post is written in Spanish, but always we have the Google translator:
By means of a tutorial example I explain how to use both winLIFE 4.0 & Femap interface to perform the multiaxial fatigue analysis of a Rotating Shaft with an internal bore hole and a cross hole. A fatigue life calculation is to be carried out for this component for a rotating movement around the middle axis.
In the simulation the "trick" used is the following: instead of rotating the shaft with a fixed load, the shaft is fixed and the load rotates around the shaft. The loading of the shaft is given in angular increments, selecting an "angular window" of 90°, which results in load application angles of 0°, 90°, 180° and 270° for a unit load of 1000N. The continuous rotating movement is shown by four load cases (in real life problems the recommendation is to use a window of 30º for accuracy reasons).
Here you are the stress results for the rotating shaft at the load application angle of 0º:
And here you are the Fatigue Damage Sum results back in FEMAP for postprocessing:
And finally here you are the Utilization Ratio results back in the FEMAP model: an utilization ratio of 1.0 signifies the endurance limit is reached. A degree of utilization of 0.044 means a 4.4% usage of the endurance limit. The Utilization Ratio is the inverts of the Safety against Endurance Limit, result computed as well by winLIFE.
Best regards, Blas.
Blas Molero Hidalgo, Ingeniero Industrial, Director IBERISA • 48004 BILBAO (SPAIN) WEB: http://www.iberisa.com Blog Femap-NX Nastran: http://iberisa.wordpress.com/