Problem with initial strain material!!!!

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Problem with initial strain material!!!!

Post by IsmBaha » Tue Apr 17, 2018 9:36 pm


I have a quick question. Is there a problem with using initial strain (or stress) material and pushing it as displacement controlled?

I created a RC simple supported beam (4 point beam) with concrete and steel as initial strain material.
- For example, when I apply a loading two 10kips , I get about a deflection of 0.5in in the middle and reactions are 10 and 10 as expected and beam carries that load without any problem.
- But instead of applying those loads, if a create a load pattern and push the beam at two points with disp control in the middle of the beam, the support reactions never get close to 10kips but get to about 2.5kips max and beam middle deformation is more than 2in. I am not sure what's going wrong in the disp control.

I remember Vesna mentioning somewhere that initial strain or stress materials might have a problem with disp control, but I can't find that post. And using the force controlled push I can't get the strength of a material after it starts softening it can't carry the monotonically increasing load, which is due to force controlled pushover.

Anyone has an idea what might be going wrong? I really appreciate any idea.

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Re: Problem with initial strain material!!!!

Post by fmk » Wed Apr 18, 2018 3:52 pm

post a small example. try not to use variable up the wazoo so i can see what the actual numbers are.

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