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View Full Version : What's wrong with these rigid diaphragms?!


smm.144
2010-04-23, 04:41 AM
When creating rigid floors robot assigns rigid link to the diaphragms.
But why they are connected to the lower left corner? shouldn't they be connected to the center?
waldemar.okapa
2010-04-23, 07:46 AM
attach the model, it looks strange.
smm.144
2010-04-23, 03:04 PM
attach the model, it looks strange.

Since I wanted to apply dead load of panels manually I created a Concrete material with name of "Conc_0" With the force density (unit weight) property set to 0.
Now I noticed the Rigid floor with that material behaviors strangely. The rigid Link is connected to the Bottom Left corner!
The reason I did not uploaded the file is because I am afraid by opening that file the materials which I have defined might be added to your Materials List and cause you some problems..
It seems that I have found another bug?!
waldemar.okapa
2010-04-23, 09:23 PM
Well, I think that the problem is indeed in this material with zero density. Program tries to calculate center of gravity for this floor, but that returns point 0,0.
Why do you define such material? The selfweight is added automatically to the first load case, but it always can be removed, check the Load table.
smm.144
2010-04-24, 07:23 AM
Well, I think that the problem is indeed in this material with zero density. Program tries to calculate center of gravity for this floor, but that returns point 0,0.
Why do you define such material? The selfweight is added automatically to the first load case, but it always can be removed, check the Load table.

Thanks Waldemar, Yes, that has caused this problem. Well I just wanted to remove the selfweight of floors but include the selfweight of beams & columns and other members... so I thought I could do that by making a zero density material. by the way do you have a better idea?
waldemar.okapa
2010-04-27, 12:06 PM
The selfwieght load can be defined for a list of objects.
Open the Load table, you can change the parameter in the SW record, to apply to (whole structure)/(object list), apply any factor for the selfweight.
ngoctanxd
2010-06-04, 12:31 AM
When creating rigid floors robot assigns rigid link to the diaphragms.
But why they are connected to the lower left corner? shouldn't they be connected to the center?

Are there definition diaphragm in RSA? What way to do that? thank!
pascal.bogdan
2010-06-04, 07:30 AM
Thanks Waldemar, Yes, that has caused this problem. Well I just wanted to remove the selfweight of floors but include the selfweight of beams & columns and other members... so I thought I could do that by making a zero density material. by the way do you have a better idea?

You can remove the self weight of the floor by choosing disregard density from modal analysis option