FEAP User Forum
FEAP => Input File Issues => Topic started by: Shuai Wang on December 03, 2020, 07:57:01 PM
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Dear all,
I would like to set a pure shear loading for 3d solid to test my user element.
I set disp BC to all external nodes with EBOU command.
I set uniform displacement in 2nd direction on z=c facet with EDIS command.
I set tangential displacement in 2nd direction on y=0 and y=b with CSURF command.
The input is something like the following. The 4th Dof is my user dof.
When I run this input, there is no displacement found on the y=0 and y=b facet. is there something wrong with the input?
Thank you for your time.
FEAP
0 0 1 3 4 8
CONStants
a = 1e5
b = 1e6
c = 1e6
MATErial 1
USER 5
*********
BLOCk
CARTesian,1,50,50,1,1,1,10
1,0.0 ,0.0, 0.0
2,a ,0.0, 0.0
3,a ,b , 0.0
4,0.0 ,b , 0.0
5,0.0 ,0.0, c
6,a ,0.0, c
7,a ,b , c
8,0.0 ,b , c
EBOUndary
3,c, 1,1,1,0
3,0, 1,1,1,0
2,b, 1,1,1,0
2,0, 1,1,1,0
1,a, 1,1,1,0
1,0, 1,1,1,0
load prop 1
edisp
3,c 0 2e4 0 0
csur
disp,2
surface
1,0,0,0,0
2,a,0,0,o
3,a,b,0,2e4
4,0,b,0,2e4
csur
disp,2
surface
1,0,0,c,0
2,0,b,c,2e4
3,a,b,c,2e4
4,a,0,c,0
load end
end
batch
init,disp
end
1 1 0 0 0 1.0
5202 0 0 0 0 1.0
batch
prop,,1
end
2 5
0 0 200 0 4800 0.9 9600 1 10000 1
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Your boundary values are scrambled. It is important to look at the output files to see what is being read.
In your particular case what you have defined is:
- Imposed displacements in x,y,z on all faces of the block (your EBOU command)
- For nodes with z=c, move them all 2e4 in the y direction, force x,z displacements to zero
- Your first csur command is looking of mesh facets on the plane z=0, whose outward normal is in the +z direction. It will find none, since there are none in your mesh. If you had a different mesh and it happened to find some it would impose a linearly increasing (with respect to x) displacement in the y direction. Note also you have an 'o' value instead of a '0' on one of the lines which is surely a typo.
- Your second csur command is looking of mesh facets on the plane z=c, whose outward normal is in the -z direction. It will find none, since there are none in your mesh. If you had a different mesh and it happened to find some it would impose a linearly increasing (with respect to x) displacement in the y direction.
- All other other boundary points will have an imposed displacement of zero.
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Maybe do a 2x2x2 problem first so you can look at the output more easily.
You can also use graphics to look at boundary conditions