CalculiX contact surfaces

[david.lambert]

I need to solve a contact problem having slightly more complicated geometry than in this problem, but is essentially quite similar. Here I have made a corner out of three fixed blocks. The fourth block is supposed to move into the corner and stop. Here's my CalculiX input file. What should it be so as to converge on the reasonable solution?
Thank you.

*NODE, NSET=Nmesh
1,0.000000000000e+000,0.000000000000e+000,-1.000000000000e+000
2,1.000000000000e+000,0.000000000000e+000,-1.000000000000e+000
3,0.000000000000e+000,1.000000000000e+000,-1.000000000000e+000
4,1.000000000000e+000,1.000000000000e+000,-1.000000000000e+000
5,0.000000000000e+000,0.000000000000e+000,0.000000000000e+000
6,1.000000000000e+000,0.000000000000e+000,0.000000000000e+000
7,0.000000000000e+000,1.000000000000e+000,0.000000000000e+000
8,1.000000000000e+000,1.000000000000e+000,0.000000000000e+000

9,-1.000000000000e+000,0.000000000000e+000,0.000000000000e+000
10,0.000000000000e+000,0.000000000000e+000,0.000000000000e+000
11,-1.000000000000e+000,1.000000000000e+000,0.000000000000e+000
12,0.000000000000e+000,1.000000000000e+000,0.000000000000e+000
13,-1.000000000000e+000,0.000000000000e+000,1.000000000000e+000
14,0.000000000000e+000,0.000000000000e+000,1.000000000000e+000
15,-1.000000000000e+000,1.000000000000e+000,1.000000000000e+000
16,0.000000000000e+000,1.000000000000e+000,1.000000000000e+000

17,0.000000000000e+000,-1.000000000000e+000,0.000000000000e+000
18,1.000000000000e+000,-1.000000000000e+000,0.000000000000e+000
19,0.000000000000e+000,0.000000000000e+000,0.000000000000e+000
20,1.000000000000e+000,0.000000000000e+000,0.000000000000e+000
21,0.000000000000e+000,-1.000000000000e+000,1.000000000000e+000
22,1.000000000000e+000,-1.000000000000e+000,1.000000000000e+000
23,0.000000000000e+000,0.000000000000e+000,1.000000000000e+000
24,1.000000000000e+000,0.000000000000e+000,1.000000000000e+000

25,5.000000000000e-002,5.000000000000e-002,5.000000000000e-002
26,9.500000000000e-001,5.000000000000e-002,5.000000000000e-002
27,5.000000000000e-002,9.500000000000e-001,5.000000000000e-002
28,9.500000000000e-001,9.500000000000e-001,5.000000000000e-002
29,5.000000000000e-002,5.000000000000e-002,9.500000000000e-001
30,9.500000000000e-001,5.000000000000e-002,9.500000000000e-001
31,5.000000000000e-002,9.500000000000e-001,9.500000000000e-001
32,9.500000000000e-001,9.500000000000e-001,9.500000000000e-001

*ELEMENT, TYPE=C3D8, ELSET=Emesh
1, 1, 2, 4, 3, 5, 6, 8, 7
2, 9, 5, 7, 11, 13, 14, 16, 15
3, 17, 18, 6, 5, 21, 22, 24, 14

4, 25, 26, 28, 27, 29, 30, 32, 31

*MATERIAL,NAME=STEEL
*ELASTIC
210000,0.3
*SOLID SECTION, Elset=Emesh, Material=STEEL

*nset,nset=fixed,generate
1,24

*boundary
fixed,1,3

**element 1 face 2 z
**element 2 face 4 x
**element 3 face 5 y
**
**element 4 face 1 z
**element 4 face 6 x
**element 4 face 3 y
*surface,name=mz
1,s2
*surface,name=mx
2,s4
*surface,name=my
3,s5
*surface,name=sz
4,s1
*surface,name=sx
4,s6
*surface,name=sy
4,s3

*CONTACT PAIR, INTERACTION=z, TYPE=Surface TO SURFACE
**slave,master
sz,mz
*SURFACE INTERACTION, NAME=z
*SURFACE BEHAVIOR, PRESSURE-OVERCLOSURE=LINEAR
10000000,0.1,0.01
*friction
0.3,1000000
*CONTACT PAIR, INTERACTION=x, TYPE=Surface TO SURFACE
**slave,master
sx,mx
*SURFACE INTERACTION, NAME=x
*SURFACE BEHAVIOR, PRESSURE-OVERCLOSURE=LINEAR
10000000,0.1,0.01
*friction
0.3,1000000
*CONTACT PAIR, INTERACTION=y, TYPE=Surface TO SURFACE
**slave,master
sy,my
*SURFACE INTERACTION, NAME=y
*SURFACE BEHAVIOR, PRESSURE-OVERCLOSURE=LINEAR
10000000,0.1,0.01
*friction
0.3,1000000

*STEP, NLGEOM, INC=200
*STATIC
*cload
32,1,-1e-8
32,2,-1e-8
32,3,-1e-8

*NODE FILE
U
*EL FILE
S
*CONTACT FILE
CDIS
*END STEP

[bernd]

Welcome to FreeCAD forum. Would you include code in code tags if you post code ... You can still edit your post in this regard. How do you created these input file. It seams not come from FreeCAD FEM?

Cheers bernd

[fandaL]

I need to solve a contact problem having slightly more complicated geometry than in this problem, but is essentially quite similar. Here I have made a corner out of three fixed blocks. The fourth block is supposed to move into the corner and stop. Here's my CalculiX input file. What should it be so as to converge on the reasonable solution?
Thank you.

I'm not experienced in tuning contact parameters, but my results show that using only one slave and one master surface converges in this case, probably since they are continuous surfaces.

Code: Select all

*surface,name=master_all
1,s2
2,s4
3,s5
*surface,name=slave_all
4,s1
4,s6
4,s3

*CONTACT PAIR, INTERACTION=z, TYPE=Surface TO SURFACE
**slave,master
slave_all,master_all
*SURFACE INTERACTION, NAME=z
*SURFACE BEHAVIOR, PRESSURE-OVERCLOSURE=LINEAR
10000000,0.1,0.01
*friction
0.3,1000000

contact_cubes_disp.png (11.36 KiB) Viewed 346 times