Large models in RSAPRO

[rbruins]

rbruins

Regarding to your scope, you are right in some cases and you are wrong in som cases.
You Can't concluse generally that modeling of panels and shear walls can be made by bars, and it is better solution.
There are more papers writen to this scope, but they give more specifics for modeling analysis and design purpose, and in most of cases they are proposed to use only in advanced analysis like push over, ore NL time history, because there are no more explained mechanism of hinge behaviour on shells, and for this purpose bar models have advantage from shell models, and in this contest your proposal is right.
Especially in robot this way of concepting is not good choice.
I tell the reason why:
If u have walls 5x0.5 m , and beams 0.5x1m and if you discretize your model with bars, and wen you make model by axis of bar elements, you have length of beams and walls(bars) greater than reality, because that part of beam which is into wall must be modeled as rigid beam, and also wall(bar) which interfree with beam must be also modeled as rigid bar(wall), and this you cant doo in robot.
This is main scope

Regards
Z.G.

Do you mean this type of structure?

Regards,

Rick

[length zero]

No i mean so
The part of beam which is put into half of wall ( from edge of wall tol axis of wall) must be modeled as rigid beam, when you model walls as bars.
And this you cant do in robot

[rbruins]

No i mean so
The part of beam which is put into half of wall ( from edge of wall tol axis of wall) must be modeled as rigid beam, when you model walls as bars.
And this you cant do in robot

Robot has rigid links, which do the same. I like the use of beam with large stiffness over rigidlinks(the loss of stiffness due to not using rigid beams is minimal).
And also you cannot obtain interaction forces from the links(as far as I know).

And I've added a small test. And for deflection no significant differences

[troy_the.best]

Do you mean this type of structure?

Regards,

Rick

i m no mean this rbruins..

what is that? tell me and explain. please

regards

ASC

[troy_the.best]

Robot has rigid links, which do the same. I like the use of beam with large stiffness over rigidlinks(the loss of stiffness due to not using rigid beams is minimal).
And also you cannot obtain interaction forces from the links(as far as I know).

And I've added a small test. And for deflection no significant differences

Dear Rbruins,
i m reviewed your model. but DL1 case vertical load. (both of them material is concrete, (panel section areas = bar section areas) then naturally results will be same. thats all. wont be different.
but use this frame in a structure and applying horizontal external loads, then results and response of structure will change. beacuse not load transfer right way.. I was trying tell to you this case.. thanks brother. see later..


best regards
falconado_turkey
ASC

[rbruins]

Dear Rbruins,
i m reviewed your model. but DL1 case vertical load. (both of them material is concrete, (panel section areas = bar section areas) then naturally results will be same. thats all. wont be different.
but use this frame in a structure and applying horizontal external loads, then results and response of structure will change. beacuse not load transfer right way.. I was trying tell to you this case.. thanks brother. see later..


best regards
falconado_turkey
ASC

This is under horizontal loading only. I tend to be lazy in the naming of my load cases. I've also removed the own-weight. As can be seen in the attachment.

[troy_the.best]

This is under horizontal loading only. I tend to be lazy in the naming of my load cases. I've also removed the own-weight. As can be seen in the attachment.

Hi friend,
sorry Rbruins but this screenshot is DL1 (vertical load only). not horizontal load. perhaps it s been wrong. see later.

falcoando
ASC

[length zero]

Dear rbruins
Using of large stiffness beams to aproach rigid beam is not good choice, because they can cause significant errors
Go tot this link http://csiberkeley.com/support_technical_papers.html and read paper Larg Numbers can cause significant errors, by Ed Wilson, and you can see that Ed in details explain this problem.

As for rigid links in robot you can't assign rigid link property, but you can make some approaches membrane panel purpose ( master nodes and slave nodes, ) but is not same rigild link behaviour used for this purpose.
If u can share your example, i will see

Regards
Z.G.

[rbruins]

Dear rbruins
Using of large stiffness beams to aproach rigid beam is not good choice, because they can cause significant errors
Go tot this link http://csiberkeley.com/support_technical_papers.html and read paper Larg Numbers can cause significant errors, by Ed Wilson, and you can see that Ed in details explain this problem.

As for rigid links in robot you can't assign rigid link property, but you can make some approaches membrane panel purpose ( master nodes and slave nodes, ) but is not same rigild link behaviour used for this purpose.
If u can share your example, i will see

Regards
Z.G.

I totally agree with you about the stiffness ratio's. As depicted in the paper normal ranges of 10 to 1000 times shouldn't cause numerical problems. My ratio in this test is 5000^4 / (500*1000^3) = 1250. I might have overdone it in this test.