Beam-Column Elements & Brick Elements in the same analys

timosidis · Post by **timosidis** » Thu Jan 20, 2005 2:34 am

I would like to use Beam-Column Elements (6DOF per joint) with Brick Elements (3DOF per joint) in a 3D-analysis. If I set:

model BasicBuilder -ndm 3 -ndf 6

when using 20Node Brick elements at the same time I get:

FATAL ERROR TwentyNodeBrick (tag:1) has different number of DOFs at its nodes

even if I fix all rotational degrees of freedom for nodes of bricks. Does anybody know a way to involve Beam-Column Elements and Brick Elements in the same analysis?
Thanks a lot.

berktaftali · Post by **berktaftali** » Thu Jan 20, 2005 4:04 am

There was a post about the same problem, but I guess it got lost somehow. Frank may help you out on this one. While you are waiting his answer, you may want to give this a try:
- define two modelBuilders (one with ndf 2, the other with ndf 3)
- define 2d elements in one, 3d elements in the other
- you have to define the boundary nodes (where the beam connects to the brick) in each modelBuilder (with same nodal coordinate), and that constrain the extra degrees of freedom.

This is what I could remember from that post. I never did it myself but it's worth a try...

Boris · Post by **Boris** » Thu Jan 27, 2005 3:50 pm

Take a look at solid02.tcl file in ExampleScripts, it does what you need...

Boris

yuanshuipi · Post by **yuanshuipi** » Thu May 19, 2005 6:38 am

In my model, soil nodes and pile nodes are not exactly same coordinate,
because the model is very complex. There're 24 foundations, each has 4 equivalent piles (different distance). The field including 19 layers soil. In order to simplify the model, the soil nodes be put in the center of 4 piles nodes.

I know that equaDOF still work in this case. I just wonder could I consider the force-distance relationship between the pile and the soil. Is there something spring element in opensees? I only find zero-length element to consider the spring element.

Thanks a lot.

silvia · Post by **silvia** » Thu May 19, 2005 12:16 pm

yuo can always use the uniaxial truss as a spring element.

yuanshuipi · Post by **yuanshuipi** » Thu May 26, 2005 5:55 pm

Can I use truss element connect one node with 3 ndf and other node with 6 ndf? Can I use zero-length element in this condition? Beside equalDOF which command can do this. I try to use rigidLink (rod) bar... ... failed. I already get results with equalDOF. But my prof. let me try something else to consider the force-displacement relation between soil and piles / soil and basement.

I tried to use truss elements and get WARNING. Can I continue?

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Beam-Column Elements & Brick Elements in the same analys

Beam-Column Elements & Brick Elements in the same analys

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