FBE vs DBE

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Layla
Posts: 9
Joined: Tue Jan 08, 2013 8:43 am

FBE vs DBE

Post by Layla »

Hi,

I'd like to simulate the NL bahavior of a 15m column and I am not sure what kind of elements I should use (force-based or displacement-based).

If I use force-based elements, then I should use one and only element with the max number of integration points for the column or can I use more than one elements for the column discretization (e.g. 15 elements for the 15m column) with 2 integration points each (in order to achieve an accuracy of the solution)? Is the 2nd solution acceptable?

On the other hand, if I use displacement-based elements, then I should increase the number of elements for the column to achieve accuracy.

Please advise.
Layla
vesna
Posts: 3033
Joined: Tue May 23, 2006 11:23 am
Location: UC Berkeley

Re: FBE vs DBE

Post by vesna »

You can achieve comparable results with either FBE or DBE.

Discretization of the FBE mostly depends on the intensity of the applied load. For smaller intensity loads (elastic range) more FBE will give you better results. As the intensity of the load increases smaller number of elements should give you better results. If the load is very high so that you expect some softening FBE is not the best element to use for that purpose but most probably 1 element with 4 or 5 integration points could be used.

As of DBE, you always need several elements along the element length. If the response is in the hardening range you probably need 8 to 12 elements. If you expect softening DBE is not the best element to use for that purpose but most probably 4 elements with 3 integration points could be used.
Pablongo
Posts: 15
Joined: Tue Oct 11, 2011 7:42 pm
Location: Georgia Tech

Re: FBE vs DBE

Post by Pablongo »

Vesna, you say neither FBE or DBE is best when softening behavior is expected. What would you suggest for this case?
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