topic Plastic hinges in Robot Structural Analysis Forum

Plastic hinges

Anonymous — Wed, 20 Jul 2016 13:53:02 GMT

Hello,

I am working on a 2D model trying to introduce plastic hinges in my bars through the non-linear tool but the same message 'Errors have been found during structure verification' comes up regardless of the hinge definition. I have also tried to model the plastic hinges by releasing the bars but the solution does not converge even for self weight. Could someone talk me through what is going on and how can i solve this issue? I have attached the model for reference.

Regards

Re: Plastic hinges

Pawel.Pulak — Fri, 22 Jul 2016 13:16:51 GMT

Hello,

the error was reported because of using the relative definition of hinge, which is not permitted for the RC members.

After changing to the definition with some direct rotation-moment relation the analysis is convergent.

I have also deleted the unnecessary user node overlapping with the hinge.

I have also used this example to show some features useful when using incremental analysis: components corresponding to appropriate load increments (attention: the order is inverted - component 1 is the last one, corresponding to the highest applied load), access to them in graphic view and in tables, calculation nodes corresponding to for instance plastic hinges, diagrams to show non-linear force-displacement relation when incrementing load.

See the video below:

Attached also the model corresponding to these steps.

---------------------------------------------
If this post answers your question please click the "Accept as Solution" button. It will help everyone to find answer more quickly!

Regards,

Re: Plastic hinges

DennisVDijk — Fri, 22 Jul 2016 13:53:38 GMT

Hello Veronica,

I looked at your model and the first warning was that there where no supports.

The error was no definition for hinge. The hinges that are defined are for steel sections. In your model I saw concrete sections. I think you have to define an hinge for your concrete section. I'm not sure thats possible in RSA.

whene I put some support in node 3 4 and 5 the model still doesnt converge. The following error accours:

I think one or more sections isn't able to take on the loads and probally buckles, critical load is smaller than the acting load.

Sorry this isnt much help for your model.

I was wondering what you try to model?