rigid link features seems does not work

[parhyang]

modeling an eccentric column with rigid link connections seems does not work properly, bending moment due to eccentricity being ignore. the results are zero, not to be expected as equal to P*e (75kn*m). this happen for both solver OOFEM and OpenSees, is this result graphics problem or the solver itself?

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[NextFEM Admin]

Dear,
this happens for 2 different reasons in both solvers:
– in the built-in solver, the rigid link is modelled with penalty method. this is equivalent to a kinematic constraint; in other words, the rigid link does not have a beam-like behaviour
– in Opensees, a kinematic constraint is applied directly with “equalDof”. Please note that this is different from “rigidLink beam” behavior (this last was the one you expected).

This is not the proper way to model this (it can interfere with rigid diaphragms) – please use a offset in the section of the element, by moving the center of the section in its properties.

[parhyang]

Dear Admin,

Thank you for explanation, the language menus make myself a little bit confuse. Looking an exported tcl files gave me an insight, it’s use equalDOF methods rather than RigidLink (beam) keywords. Differentiation about these two methods are lay on eccentricity being consider or not. A further implementation to switch of both methods in menus could be useful.

Regarding to modeling these condition using offset methods as recommended, still the bending moment due eccentricity being ignore by internal solver (OOFEM) or OpenSees.

Regards,

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[NextFEM Admin]

Thanks for your feedback. Yes, eccentricity in section is useful in verifications, it does not reports moments as you wanted to.
We’ll introduce an option in the next update to switching from one to another approach.

[parhyang]

Thank you for interested such a features so the user does not need to be modified manually. seems reading result from RigidLink methods are working good for the graphic interfaces. Below is an output from modified tcl files by importing and perform analysis.

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[NextFEM Admin]

We released a minor patch, no need to change any option.
Please use command ?/Updates/Check for minor updates.

[parhyang]

Thank you for updating, but seems I did not succeed to updates using these commands. Only blipped display, no more info shown, restarting application and displaying version in About dialog menu’s given info as version 1.70p0

will downloading and reinstalling the programs make it works?

[NextFEM Admin]

Yes, try downloading it again. Version is 1.7p0

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