Learning Forum

[javat33489]

Hello everyone.

I am doing a drill fatigue calculation and also using thermal analysis.

Tell me, will thermal analysis affect fatigue in fatigue calculations?

For fatigue, the SN curve will be used and for thermal analysis, the MAT_THERMAL_ISOTROPIC map will be used.

Thank you.

[javat33489]

I made two calculations with and without thermal analysis. The stress results are the same. So thermal data does not affect fatigue, but only provides additional information about temperature.

[Reno Genest]

Hello Javat,

For thermal loading fatigue, a solution in time domain is required (*FATIGUE and *MAT_ADD_FATIGUE). There is more information in the LS-DYNA User Manual:

"*MAT_ADD_FATIGUE is applicable to frequency domain fatigue analysis,
defined by the keywords: *FREQUENCY_DOMAIN_RANDOM_VIBRATION_
FATIGUE and *FREQUENCY_DOMAIN_SSD_FATIGUE. It also applies
to time domain fatigue analysis, defined by the keyword *FATIGUE (see these
keywords for further details)."

Try to load the structure with *LOAD_THERMAL_LOAD_CURVE and use *MAT_ELASTIC_PLASTIC_THERMAL as your material model.

 

Let me know how it goes.

 

Reno.