plastic hinge in pushover analysis

arash1985us · Post by **arash1985us** » Wed Oct 07, 2009 12:43 am

Dear Dr. Silva:
How can I see where the plastic hinge are formed in 2D frame with fiber section and nonlinear beam-column element?

silvia · Post by **silvia** » Wed Oct 07, 2009 6:45 am

if you want to watch it grow, you should use many displacement-based beam-column elements.
with the force-based nbc element, plasticity is forced at the integration point and the hinge length is equal to the integration-point weight.

arash1985us · Post by **arash1985us** » Wed Oct 07, 2009 12:25 pm

Thanks Dr.Silvia;
so, you mean:
1-I must use displacement-based nonlinear beam-column elements instead of forced-based ones in pushover?,and
2-how should I adjust the records?Should I record moments at each node of elements and compare with plastic moments to see where the plastic hinge are formed?

silvia · Post by **silvia** » Wed Oct 07, 2009 1:37 pm

it's up to you on how you define it.

emanueletrainini · Post by **emanueletrainini** » Wed Nov 30, 2011 8:55 am

arash1985us wrote:
> Thanks Dr.Silvia;
> so, you mean:
> 1-I must use displacement-based nonlinear beam-column elements instead of
> forced-based ones in pushover?,and
> 2-how should I adjust the records?Should I record moments at each node of
> elements and compare with plastic moments to see where the plastic hinge
> are formed?

about (2). It can brings to some mistake IMHO. As you are in charge of setting moments lenght, it could result in a very low accurate evaluation. Isn't it?

esi_opensees · Post by **esi_opensees** » Fri Dec 09, 2011 7:43 am

I think you need to do a post-process step. You can use stressStrain as a argument of “recorder element”, draw the stress-strain curve, and see that material nonlinearity has been reached or not.
Any opinion?

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plastic hinge in pushover analysis

plastic hinge in pushover analysis

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