Residual stressses in FEA 1

[kins]

Hi friends,

Could anyone let me know as to how one can use residual stresses in FEA (ABAQUS). It would be very helpful if anyone can direct me to any information on this matter.

Thanks

 

[afshin]

Dear Kins,

It depends what is the purpose of Residual stress (RS) consideration. If you want to get the precise stress profile, then you must have the exact profile (distribution) of the RS and add to (For tensile RS) or substract it (for compressive RS) from the applied stress on your component and then include the resultant into your finite element model as a new applied stress (load) condition. The problem is that always finding the absolute value (or distribution) of the RS is not an easy task, but if you have it then there is no problem to do as I explained.

Regards

Afshin

 

[brad]

Please be more specific in your question. Residual stress is "used" to address the real stress state. A classic example is forming stresses. Many codes discount forming stresses in parts; when these stresses (which are residual stresses) are accounted for properly, often the results of the analysis change considerably from the case in which they are not considered.
Brad

 

[kins]

To be specific

We do fe analysis of a wheel hubs for the forces arising due to the cornering effect. A part of the wheel hub is formed. From the stress values obtained in this analysis we calculate the fatigue factor of safety. Now I want to use the residual stresses arising during forming operation as well as the ones during forging process.

I hope this will help Brad to give me clear idea.

Thanks
Kins

 

[tld23]

Kins,
remember for fatigue analyses, residual stresses only influence the mean stress and not the stress range.

If these are unwelded materials you can use the Goodman rule (or Soderberg or Gerber rules) to correct for the mean stress effects.

If these are welded components the welding residual stresses will usually be (or be assumed to be) of yield magnitude tension and you should be using SN curves that relate to your specific type of weld.

TERRY