node order of stdBrick and other 8 points brick element

[yuanshuipi]

I wonder why node's order of stdBrick is different with other brick elements?

I set the variable "stdsoil" to consider the brick element. Firstly use stdBrick to bulid up the model. I plan later change the brick element Bbarbrick or other 8 points brick element. Since I notice that all the node's order is same in the previous manual.
But I found the node's order of stdBrick is different with other brick in the last manual. I'm a little confused, Why?
The brick elements for the top layers is not very regular due to a basement. It is difficult to check all data again. Any advise?

[fmk]

they were written by 2 different people with different ideas on how bricks should be numbered. the structural people typically use one & the geotech's the other. getting
one group to change to the other has not happened because too many scripts have
been created and nobody wants to redo theirs.

[yuanshuipi]

Thanks a lot!

So I plan set a if-else statement to make sure the node's order for different brick elements. It is great since I should add some more parameter to Brick8N element. At same time I plan to modify my tcl file to avoid repeat element command too much times.

Another question is where I can find the detail description of those brick elements?

In google search NO Bbarbrick & Birck8N has been found other than opensees. It seems Bbarbrick and stdBrick was write by same people from the information in the CPP files.
Brick8N was developed by Boris Jeremic, Zhaohui Yang and Xiaoyan Wu from CPP files. I can search their publishment.

Any further advise is appreciated.

[silvia]

i would definitely go to Boris' web site, as he has a lot of additional information and class notes there.

[Boris]

Hello There,

the node numbering we used is from
a book by Bathe and Wilson:

@book{local-81,
author = { Bathe, Klaus-J\"{u}rgen and
Wilson, Edward, L. },
year = { 1976 },
title = { Numerical Methods in
Finite Element Analysis },
publisher = { Prentice Hall Inc. },
note = { },
napomena = { local CM81,TA 347 F5. B37 ;
ISBN 0 -- 13 - 627190 - 1 },
}

which is the same in all subsuequent books by Bathe...

Nothing special about this numbering scheme, it is just one of the first FEM books I used as a references when programing 15 years ago...

See my lectures note for more info (this is section about that brick element):

http://sokocalo.engr.ucdavis.edu/~jerem ... node4.html

or use the PDF version as it preserves graphs better (have to figure out why are figures messed up in html version...).

Boris

[yuanshuipi]

Actually I already enter Boris website though I forget to mention. Thanks Silvia wake me up that I should enter there again with more clear purpose.

Thanks for Boris. I also readed Bathe's book "Numerical Methods in Finite Element Analysis" while developing a program for eigen value of beam element structure.
Sorry for misleading. Node order is not a problem now. I already change my TCL file with 7 brick element statement. The eigen calculation use 36 min. in my computer. It is worth changing because the files more flexible now.

My problem is how to choose a proper brick elements. From the parameter I guess that Brick8N for consider body force, U_P_U for solid and liquid interaction. Is there anything more? And what is the difference between the stdBrick and bBarbrick. In the beginning analysis should I use rigidLink for pile's cap while bBarbrick for the soil?

Next my concern should be the combination of the pile and basement with the soil. Further next is application the absorbing boundary.
It is first time for me to use 3D brick element to consider the soil. It is wonderful to using OPENSEES. It is more wonderful to have a chance to receive so much help here.

[lahlou]

Dear Mister,

I would like to know how can use absorbing boundary in dynamic soil study for OpenSees.

Please answer me at this email : dridife@ymail.com

Best reguards