Possible bug using *Contact print

[Matej]

I have prepared a model of two parts in contact as seen in the bottom image (I am using 2D plane stress for simplicity reasons). The problem is, that when I add a *Contact print card the simulation ends without the results - fails, but when I remove the *Contact print card the simulation ends successfully with results. This only happens for the node-to-surface contact and the output variable CF:

*Contact print, Master=Internal_Selection-1_Cp-1_Master, Slave=Internal_Selection-1_Cp-1_Slave
CF

The input file can be downloaded at: Dropbox - Contact_Err.inp - Simplify your life

I have tested the simulation on Windows 10 using CalculiX 2.18. Can somebody confirm the problem before we bother Guido?

[Calc_em]

It seems that it’s not a bug but rather a limitation. Apparently, the print of contact forces can’t be requested for a node to surface contact. Quoting the documentation:

The quantities CF, CFN and CFS represent the total force, total normal force and total shear force acting on the slave surface, respectively, for a selected face-to-face penalty contact pair.

[Matej]

I agree that it is a limitation but the problem is that the simulation starts, goes through all iterations to find an equilibrium solution and then fails to write the results. Any results.

As I see it, other results (U, S, E, …) should be saved for the user not to lose time.

[Calc_em]

That’s right, a limitation shouldn’t be handled this way, especially since it can be very confusing for the user. The solver should produce an error or warning message to make it clear what’s going on. And, as you said, the best way would be to make the solver warn about invalid output request, ignore it and carry on with the analysis writing other results.

@dhondt Could you consider fixing the current behavior in this regard ?

[Matej]

That is exactly what I had in mind. Thank you.

[fgr]

Hi All
I could use a little help, because what I believe must be bugs could also be my misunderstand, so please correct me if I’m wrong.

I have this simple model consisting of 3 C3D8 elements, with one element on top doing a static sliding fort, back & fort under gravity load. The top/bottom elements are connected by face to face contact elements and the forced movements are attacked in the friction plane to avoid any derived forces/moments. CCX_2.22 has been used for simulation.

*Node
1, 0.0,  0.0,   0.0
2, 0.1,  0.0,   0.0
3, 0.0, -0.05,  0.0
4, 0.1, -0.05,  0.0
5, 0.0,  0.0,   0.2
6, 0.0, -0.05,  0.2
7, 0.1,  0.0,   0.2
8, 0.1, -0.05,  0.2
9, 0.0,  0.0,  -0.01
10, 0.1,  0.0,  -0.01
11, 0.0,  0.05, -0.01
12, 0.1,  0.05, -0.01
13, 0.0,  0.0,   0.09
14, 0.0,  0.05,  0.09
15, 0.1,  0.0,   0.09
16, 0.1,  0.05,  0.09
17, 0.0,  0.0,   0.1
18, 0.0, -0.05,  0.1
19, 0.1,  0.0,   0.1
20, 0.1, -0.05,  0.1
**
*Element, Type=C3D8, Elset=Fixed_Brick
61, 4, 2, 1, 3, 20, 19, 17, 18
62, 20, 19, 17, 18, 8, 7, 5, 6
*Element, Type=C3D8, Elset=Moved_Brick
63, 9, 10, 12, 11, 13, 15, 16, 14
*Elset, Elset=Eall
61, 62, 63
**
*Nset, Nset=Master
1, 2, 5, 7, 17, 19
*Nset, Nset=Slave
9, 10, 13, 15
*Nset, Nset=Fixed_Node
3, 4, 6, 8, 18, 20
*Nset, Nset=Attack_Node
9, 10
**
*Elset, Elset=Solids
Fixed_Brick, 
Moved_Brick
**
*Surface, Name=master, Type=Element
Fixed_Brick, S4
*Surface, Name=slave, Type=Element
Moved_Brick, S3
**
*Material, Name=Steel
*Density
7800
*Elastic
2.1e+11, 0.28
**
*Solid section, Elset=Solids, Material=Steel
**
*Surface interaction, Name=Surf_Contact
*Surface behavior, Pressure-overclosure=Linear
1.0e+12, 2.86e+6
*Friction
0.1, 100000000
**
*Contact pair, Interaction=Surf_Contact, Type=Surface to surface, Adjust=0
slave, master
**
*Amplitude, Name=move_z
0,          0, 
0.08333333, 0.01, 
0.16666667, 0.02,
0.25,       0.03,
0.33333333, 0.04,
0.41666667, 0.05, 
0.5,        0.06, 
0.58333333, 0.07, 
0.66666667, 0.08, 
0.75,       0.09, 
0.83333333, 0.1,
0.91666666, 0.11, 
1,          0.12,
1.08333333, 0.11, 
1.16666667, 0.1,
1.25,       0.09,
1.33333333, 0.08,
1.41666667, 0.07, 
1.5,        0.06, 
1.58333333, 0.05, 
1.66666667, 0.04, 
1.75,       0.03, 
1.83333333, 0.02,
1.91666666, 0.01, 
2,          0.0
2.08333333, 0.01, 
2.16666667, 0.02,
2.25,       0.03,
2.33333333, 0.04,
2.41666667, 0.05, 
2.5,        0.06, 
2.58333333, 0.07, 
2.66666667, 0.08, 
2.75,       0.09, 
2.83333333, 0.1,
2.91666666, 0.11, 
3,          0.12,
*Amplitude, Name=gravity_preload
0, 1
**
*Step, Nlgeom, Inc=100
*Static, Solver=Pardiso
0.0833333, 3, 1E-05, 0.0833333
**
*Boundary
Fixed_Node, 1, 6, 0
*Boundary, Amplitude=move_z
Attack_Node, 3, 3, 1
**
*Dload, Amplitude=gravity_preload
Moved_Brick, Grav, 9.82, 0, -1, 0
**
*Node print, Nset=Attack_Node, Totals=Only, Global=Yes
RF, U
*El print, Elset=Moved_Brick, Totals=Only, Global=Yes
S, ENER
*Contact print, Totals=Only, Master=master, Slave=slave
CSTR, CELS, CNUM, CF
**
*Node file
RF, U
**
*End step

When I activate the “*Contact Print” card I can get some statistic of the active contact surfaces.

Looking into the xxx.dat file for step time 0.8333330E-01 the following values are reported for the active contact surface

 statistics for slave set SLAVE, master set MASTER and time  0.8333330E-01

   total surface force (fx,fy,fz) and moment about the origin (mx,my,mz)

    2.425732E-18  3.829800E+01 -3.829800E+00 -1.914900E+00  1.914900E-01  1.914900E+00

   center of gravity and mean normal

    5.000000E-02 -5.047526E-09  5.500000E-02  0.000000E+00 -1.000000E+00  0.000000E+00

   moment about the center of gravity(mx,my,mz)

    1.914900E-01  0.000000E+00  2.220446E-16

   area,  normal force (+ = tension) and shear force (size)

    9.000000E-03 -3.829800E+01  3.829800E+00

center of gravity
Since corner of current contact surfaces are located at origin at time step 0.8333330E-01, I expect X and Z values to be equal for the center of gravity.

moment about the center of gravity(mx,my,mz)
I really don’t understand these values, I would have expected surface moments of inertia, but the values doesn’t make sense to me, at least I would expect mx and mz to be equal for a squared surface, but maybe someone can explain ?

area
For time step 0.8333330E-01, I expect the area to be 1.000000E-02

Further it also seems like the values for contact spring energy has been delayed with a single time step. I would have expected the dashed curve for the contact spring energy

Thanks in advantage

[Disla]

Hi,

Fast response, “moment about the….” is not Moment of inertia [mm4] but Moment straightforward [ N ] x [mm]
From my point of view, you have too many things going on to isolate the problem and see it.
I would start form a static cube supported in plane Z=0, no friction , uniform surface traction on top and no Poisson ratio. Cube Offset from the origin to check your traction is inducing the expected Moments with respect the origin and the Center of gravity. (See example inp)
Keep in mind contact stiffness could be relaxed for convergence purposes. Check final values.

*NODE
1,0,0,1
2,1,0,1
3,-3.048,-3.048,-10
4,-3.048,3.048,0
5,-3.048,-3.048,0
6,3.048,-3.048,0
7,-3.048,3.048,-10
8,3.048,3.048,-10
9,3.048,-3.048,-10
10,3.048,3.048,0
11,1,1,1
12,0,1,1
13,0,0,0
14,0,-2.22044604925E-16,0
15,0,0,0
16,1,0,0
17,1,1,0
18,0,1,0
19,0,0,0.5
20,0,0.5,0
21,0,0.5,0.5
22,0,0.5,1
23,0,1,0.5
24,0.5,0,0
25,0.5,0,0.5
26,0.5,0,1
27,0.5,0.5,0
28,0.5,0.5,0.5
29,0.5,0.5,1
30,0.5,1,0
31,0.5,1,0.5
32,0.5,1,1
33,1,0,0.5
34,1,0.5,0
35,1,0.5,0.5
36,1,0.5,1
37,1,1,0.5
*ELEMENT,TYPE=C3D8
1,28,35,37,31,29,36,11,32
2,8,7,3,9,10,4,5,6
3,15,24,27,20,19,25,28,21
4,19,25,28,21,1,26,29,22
5,20,27,30,18,21,28,31,23
6,21,28,31,23,22,29,32,12
7,24,16,34,27,25,33,35,28
8,25,33,35,28,26,2,36,29
9,27,34,17,30,28,35,37,31
*NSET,NSET=N_BALL
1
2
11
12
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
*ELSET,ELSET=BALL
1
3
4
5
6
7
8
9
*ELSET,ELSET=BASE
2
*SURFACE,NAME=SLAVE
9,S1
7,S1
5,S1
3,S1
*SURFACE,NAME=DRUMS
2,S2
*SURFACE,NAME=AMY
2,S1
2,S3
2,S4
2,S5
2,S6
*MATERIAL,NAME=MATERIAL
*ELASTIC,TYPE=ISOTROPIC
210000000000,0.3
*DENSITY
1000
*SOLID SECTION,ELSET=BALL,MATERIAL=MATERIAL
*SOLID SECTION,ELSET=BASE,MATERIAL=MATERIAL
*BOUNDARY
1,2,,0
2,1,,0
2,2,,0
3,1,,0
3,2,,0
3,3,,0
4,1,,0
4,2,,0
4,3,,0
5,1,,0
5,2,,0
5,3,,0
6,1,,0
6,2,,0
6,3,,0
7,1,,0
7,2,,0
7,3,,0
8,1,,0
8,2,,0
8,3,,0
9,1,,0
9,2,,0
9,3,,0
10,1,,0
10,2,,0
10,3,,0
11,1,,0
15,2,,0
16,1,,0
16,2,,0
17,1,,0
19,2,,0
24,2,,0
25,2,,0
26,2,,0
33,1,,0
33,2,,0
34,1,,0
35,1,,0
36,1,,0
37,1,,0
*CONTACT PAIR,INTERACTION=SI_2,TYPE=SURFACE TO SURFACE
SLAVE,DRUMS
*SURFACE INTERACTION,NAME=SI_2
*SURFACE BEHAVIOR,PRESSURE-OVERCLOSURE=HARD
*STEP
*STATIC
*CLOAD
1,3,-62500
26,3,-125000
29,3,-250000
22,3,-125000
2,3,-62500
36,3,-125000
32,3,-125000
12,3,-62500
11,3,-62500
*NODE FILE,GLOBAL=YES,CONTACT ELEMENTS
U,RF
*EL FILE
ENER,S,NOE
*Contact print, Totals=Only, Master=DRUMS, Slave=SLAVE
CF

*END STEP

[fgr]

@Disla
I fully agree with your example, and in trying to keep it simple, my problem is, that calculating every step as an isolated incident doesn’t necessary provoke any bugs. As an example the isolated calculation of time step 0.8333330E-01 will reports mx = 0,
I believe that every will agree, that within the classic physics, static moment about the center of gravity will always be zero, so please explain to me how these peaks occur when mx in my mindset is expected to be zero for every time step.

[Disla]

@fgr

static moment about the center of gravity will always be zero

If contact pressure is not symmetric respect to the CG there will be net moment about the CG. Your contact pressure is very irregular and changes across the path isn’t it.
Seems like, its higher close to master transitions.

By the way your contact doesn’t satisfy the slave finer/ master coarser rule.

[fgr]

@Disla, I really appreciate your response.
I need to confess, I didn’t was aware of the exact definition of these moments, center of gravity for current active contact elements in balance with center for down force, which in my mindset explain the reported results.

Further I also didn’t paid sufficient attention to behavior of contact elements in ccx, where the number of contact element isn’t updated between the iterations within the same time step.
In my simulation the area of active contact surface starts as linear then pass a singularity, being constant pass a singularity again and end up as linear.

Due to this behavior, the result after a singularity will always be more or less converged due to the step size the singularity has been approached with. It can easily be illustrated in the following graphs.

[Disla]

Precipitating the cube on a “cliff” can also provide a better understanding of how the contact works. The contact/support area under the cube disappears linearly and so should increase the momentum around the CG.

What I have found that I still do not understand is that nmber CNUM of contact elements increase close to Master element transitions. I can’t explain that. He seems to work like a monkey who won’t let go of the branch until he has a good grip on the next one.

[fgr]

@Disla You’re not alone , I don’t understand it either. Try to look at my dataset, where the brick are going fort, back and fort again, when the brick is moving in positive z-direction, it can generate up to 70 contact elements but when going in negative z-direction with same steps it will only generate 56 contact elements.
In my mindset I would expect the number of contact elements to be periodic since the only difference are direction of movement. I have also tried to mirror my dataset in the xy-plane, but gave exact the same curve so it isn’t the sign in movement that generate the asymmetric curve

[Disla]

Just to point that I’m not saying CNUM it’s wrong. Those jumps in the number of contact elements doesn’t seem to affect the CPRESS or Moment about the CG values. At least not in my example. It’s just that there are more elements than I would expect but maybe they are not participating?¿?

What doesn’t seem right to me is the value of contact surface pressure at the area without support. There is an increae in maximum surface pressure value as I would expect . There is less contat/supporting surface for the same external force. Higher pressure seems ok to me but not to show up at the corner.

Surface to Surface Contact

Mortar contact delivers a much more reasonable solution to me. Pressure increase where there is still contact before overturning (around the center of the cube base).

Mortar Contact

*Node
1, 0.00000000E+000, 0.00000000E+000, 1.00000000E+000
2, 1.00000000E+000, 0.00000000E+000, 1.00000000E+000
3, -1.00000000E+000, -3.04800000E+000, -1.00000000E+001
4, -1.00000000E+000, 3.04800000E+000, 0.00000000E+000
5, -1.00000000E+000, -3.04800000E+000, 0.00000000E+000
6, 1.20000000E+001, -3.04800000E+000, 0.00000000E+000
7, -1.00000000E+000, 3.04800000E+000, -1.00000000E+001
8, 1.20000000E+001, 3.04800000E+000, -1.00000000E+001
9, 1.20000000E+001, -3.04800000E+000, -1.00000000E+001
10, 1.20000000E+001, 3.04800000E+000, 0.00000000E+000
11, 1.00000000E+000, 1.00000000E+000, 1.00000000E+000
12, 0.00000000E+000, 1.00000000E+000, 1.00000000E+000
13, 0.00000000E+000, 0.00000000E+000, 0.00000000E+000
14, 0.00000000E+000, -2.22044605E-016, 0.00000000E+000
15, 0.00000000E+000, 0.00000000E+000, 0.00000000E+000
16, 1.00000000E+000, 0.00000000E+000, 0.00000000E+000
17, 1.00000000E+000, 1.00000000E+000, 0.00000000E+000
18, 0.00000000E+000, 1.00000000E+000, 0.00000000E+000
19, 0.00000000E+000, 0.00000000E+000, 5.00000000E-001
20, 0.00000000E+000, 5.00000000E-001, 0.00000000E+000
21, 0.00000000E+000, 5.00000000E-001, 5.00000000E-001
22, 0.00000000E+000, 5.00000000E-001, 1.00000000E+000
23, 0.00000000E+000, 1.00000000E+000, 5.00000000E-001
24, 5.00000000E-001, 0.00000000E+000, 0.00000000E+000
25, 5.00000000E-001, 0.00000000E+000, 5.00000000E-001
26, 5.00000000E-001, 0.00000000E+000, 1.00000000E+000
27, 5.00000000E-001, 5.00000000E-001, 0.00000000E+000
28, 5.00000000E-001, 5.00000000E-001, 5.00000000E-001
29, 5.00000000E-001, 5.00000000E-001, 1.00000000E+000
30, 5.00000000E-001, 1.00000000E+000, 0.00000000E+000
31, 5.00000000E-001, 1.00000000E+000, 5.00000000E-001
32, 5.00000000E-001, 1.00000000E+000, 1.00000000E+000
33, 1.00000000E+000, 0.00000000E+000, 5.00000000E-001
34, 1.00000000E+000, 5.00000000E-001, 0.00000000E+000
35, 1.00000000E+000, 5.00000000E-001, 5.00000000E-001
36, 1.00000000E+000, 5.00000000E-001, 1.00000000E+000
37, 1.00000000E+000, 1.00000000E+000, 5.00000000E-001
38, 5.50000000E+000, 3.04800000E+000, -1.00000000E+001
39, 5.50000000E+000, 3.04800000E+000, 0.00000000E+000
40, 5.50000000E+000, -3.04800000E+000, -1.00000000E+001
41, 5.50000000E+000, -3.04800000E+000, 0.00000000E+000
42, 7.50000000E-001, 5.00000000E-001, 5.00000000E-001
43, 1.00000000E+000, 7.50000000E-001, 5.00000000E-001
44, 7.50000000E-001, 1.00000000E+000, 5.00000000E-001
45, 5.00000000E-001, 7.50000000E-001, 5.00000000E-001
46, 5.00000000E-001, 5.00000000E-001, 7.50000000E-001
47, 1.00000000E+000, 5.00000000E-001, 7.50000000E-001
48, 1.00000000E+000, 1.00000000E+000, 7.50000000E-001
49, 5.00000000E-001, 1.00000000E+000, 7.50000000E-001
50, 7.50000000E-001, 5.00000000E-001, 1.00000000E+000
51, 1.00000000E+000, 7.50000000E-001, 1.00000000E+000
52, 7.50000000E-001, 1.00000000E+000, 1.00000000E+000
53, 5.00000000E-001, 7.50000000E-001, 1.00000000E+000
54, 2.50000000E-001, 0.00000000E+000, 0.00000000E+000
55, 5.00000000E-001, 2.50000000E-001, 0.00000000E+000
56, 2.50000000E-001, 5.00000000E-001, 0.00000000E+000
57, 0.00000000E+000, 2.50000000E-001, 0.00000000E+000
58, 0.00000000E+000, 0.00000000E+000, 2.50000000E-001
59, 5.00000000E-001, 0.00000000E+000, 2.50000000E-001
60, 5.00000000E-001, 5.00000000E-001, 2.50000000E-001
61, 0.00000000E+000, 5.00000000E-001, 2.50000000E-001
62, 2.50000000E-001, 0.00000000E+000, 5.00000000E-001
63, 5.00000000E-001, 2.50000000E-001, 5.00000000E-001
64, 2.50000000E-001, 5.00000000E-001, 5.00000000E-001
65, 0.00000000E+000, 2.50000000E-001, 5.00000000E-001
66, 0.00000000E+000, 0.00000000E+000, 7.50000000E-001
67, 5.00000000E-001, 0.00000000E+000, 7.50000000E-001
68, 0.00000000E+000, 5.00000000E-001, 7.50000000E-001
69, 2.50000000E-001, 0.00000000E+000, 1.00000000E+000
70, 5.00000000E-001, 2.50000000E-001, 1.00000000E+000
71, 2.50000000E-001, 5.00000000E-001, 1.00000000E+000
72, 0.00000000E+000, 2.50000000E-001, 1.00000000E+000
73, 5.00000000E-001, 7.50000000E-001, 0.00000000E+000
74, 2.50000000E-001, 1.00000000E+000, 0.00000000E+000
75, 0.00000000E+000, 7.50000000E-001, 0.00000000E+000
76, 5.00000000E-001, 1.00000000E+000, 2.50000000E-001
77, 0.00000000E+000, 1.00000000E+000, 2.50000000E-001
78, 2.50000000E-001, 1.00000000E+000, 5.00000000E-001
79, 0.00000000E+000, 7.50000000E-001, 5.00000000E-001
80, 0.00000000E+000, 1.00000000E+000, 7.50000000E-001
81, 2.50000000E-001, 1.00000000E+000, 1.00000000E+000
82, 0.00000000E+000, 7.50000000E-001, 1.00000000E+000
83, 7.50000000E-001, 0.00000000E+000, 0.00000000E+000
84, 1.00000000E+000, 2.50000000E-001, 0.00000000E+000
85, 7.50000000E-001, 5.00000000E-001, 0.00000000E+000
86, 1.00000000E+000, 0.00000000E+000, 2.50000000E-001
87, 1.00000000E+000, 5.00000000E-001, 2.50000000E-001
88, 7.50000000E-001, 0.00000000E+000, 5.00000000E-001
89, 1.00000000E+000, 2.50000000E-001, 5.00000000E-001
90, 1.00000000E+000, 0.00000000E+000, 7.50000000E-001
91, 7.50000000E-001, 0.00000000E+000, 1.00000000E+000
92, 1.00000000E+000, 2.50000000E-001, 1.00000000E+000
93, 1.00000000E+000, 7.50000000E-001, 0.00000000E+000
94, 7.50000000E-001, 1.00000000E+000, 0.00000000E+000
95, 1.00000000E+000, 1.00000000E+000, 2.50000000E-001
**
** Elements ++++++++++++++++++++++++++++++++++++++++++++++++
**
*Element, Type=C3D20R, Elset=Solid_part-1
1, 28, 35, 37, 31, 29, 36, 11, 32, 42, 43, 44, 45, 50, 51, 52,
53, 46, 47, 48, 49
3, 15, 24, 27, 20, 19, 25, 28, 21, 54, 55, 56, 57, 62, 63, 64,
65, 58, 59, 60, 61
4, 19, 25, 28, 21, 1, 26, 29, 22, 62, 63, 64, 65, 69, 70, 71,
72, 66, 67, 46, 68
5, 20, 27, 30, 18, 21, 28, 31, 23, 56, 73, 74, 75, 64, 45, 78,
79, 61, 60, 76, 77
6, 21, 28, 31, 23, 22, 29, 32, 12, 64, 45, 78, 79, 71, 53, 81,
82, 68, 46, 49, 80
7, 24, 16, 34, 27, 25, 33, 35, 28, 83, 84, 85, 55, 88, 89, 42,
63, 59, 86, 87, 60
8, 25, 33, 35, 28, 26, 2, 36, 29, 88, 89, 42, 63, 91, 92, 50,
70, 67, 90, 47, 46
9, 27, 34, 17, 30, 28, 35, 37, 31, 85, 93, 94, 73, 42, 43, 44,
45, 60, 87, 95, 76
*Element, Type=C3D8I, Elset=Solid_part-2
2, 38, 7, 3, 40, 39, 4, 5, 41
10, 8, 38, 40, 9, 10, 39, 41, 6
**
** Node sets +++++++++++++++++++++++++++++++++++++++++++++++
**
*Nset, Nset=Node_Set-y
22, 36
*Nset, Nset=Internal-1_Surface-X
1, 12, 15, 18, 19, 20, 21, 22, 23, 57, 58, 61, 65, 66, 68, 72, 
75, 77, 79, 80, 82
*Nset, Nset=Internal-1_Internal_Selection-1_Surface_Traction-1
1, 2, 11, 12, 22, 26, 29, 32, 36, 50, 51, 52, 53, 69, 70, 71, 
72, 81, 82, 91, 92
*Nset, Nset=Internal-1_Rigi-Z
3, 4, 5, 6, 7, 8, 9, 10, 38, 39, 40, 41
*Nset, Nset=Internal-1_Rigi-Y
3, 4, 5, 6, 7, 8, 9, 10, 38, 39, 40, 41
*Nset, Nset=Internal-1_Rigi-X
3, 4, 5, 6, 7, 8, 9, 10
*Nset, Nset=Internal-1_Internal_Selection-1_Uniform_Pressure-1
1, 2, 11, 12, 22, 26, 29, 32, 36, 50, 51, 52, 53, 69, 70, 71, 
72, 81, 82, 91, 92
*Nset, Nset=Node_Set-X
5, 15, 18
*Nset, Nset=Internal-1_Surface-MAster
4, 5, 6, 10, 39, 41
*Nset, Nset=Internal-1_Surface-Slave
15, 16, 17, 18, 20, 24, 27, 30, 34, 54, 55, 56, 57, 73, 74, 75, 
83, 84, 85, 93, 94
**
** Element sets ++++++++++++++++++++++++++++++++++++++++++++
**
*Elset, Elset=Internal_Selection-1_Solid_Section-1
Solid_part-1, 
Solid_part-2
*Elset, Elset=Internal-1_Surface-X_S6
3, 4, 5, 6
*Elset, Elset=Internal-1_Internal_Selection-1_Surface_Traction-1_S2
1, 4, 6, 8
*Elset, Elset=Internal-1_Rigi-Z_S1
2, 10
*Elset, Elset=Internal-1_Rigi-Z_S3
2, 10
*Elset, Elset=Internal-1_Rigi-Z_S4
2
*Elset, Elset=Internal-1_Rigi-Z_S5
2, 10
*Elset, Elset=Internal-1_Rigi-Z_S6
10
*Elset, Elset=Internal-1_Rigi-Y_S3
2, 10
*Elset, Elset=Internal-1_Rigi-Y_S5
2, 10
*Elset, Elset=Internal-1_Rigi-X_S4
2
*Elset, Elset=Internal-1_Rigi-X_S6
10
*Elset, Elset=Internal_Selection-1_Gravity-1
Solid_part-1
*Elset, Elset=Internal-1_Internal_Selection-1_Uniform_Pressure-1_S2
1, 4, 6, 8
*Elset, Elset=Internal-1_Surface-MAster_S2
2, 10
*Elset, Elset=Internal-1_Surface-Slave_S1
3, 5, 7, 9
**
** Surfaces ++++++++++++++++++++++++++++++++++++++++++++++++
**
*Surface, Name=Surface-X, Type=Element
Internal-1_Surface-X_S6, S6
*Surface, Name=Internal_Selection-1_Surface_Traction-1, Type=Element
Internal-1_Internal_Selection-1_Surface_Traction-1_S2, S2
*Surface, Name=Rigi-Z, Type=Element
Internal-1_Rigi-Z_S1, S1
Internal-1_Rigi-Z_S3, S3
Internal-1_Rigi-Z_S4, S4
Internal-1_Rigi-Z_S5, S5
Internal-1_Rigi-Z_S6, S6
*Surface, Name=Rigi-Y, Type=Element
Internal-1_Rigi-Y_S3, S3
Internal-1_Rigi-Y_S5, S5
*Surface, Name=Rigi-X, Type=Element
Internal-1_Rigi-X_S4, S4
Internal-1_Rigi-X_S6, S6
*Surface, Name=Internal_Selection-1_Uniform_Pressure-1, Type=Element
Internal-1_Internal_Selection-1_Uniform_Pressure-1_S2, S2
*Surface, Name=Surface-MAster, Type=Element
Internal-1_Surface-MAster_S2, S2
*Surface, Name=Surface-Slave, Type=Element
Internal-1_Surface-Slave_S1, S1
**
** Physical constants ++++++++++++++++++++++++++++++++++++++
**
**
** Coordinate systems ++++++++++++++++++++++++++++++++++++++
**
**
** Materials +++++++++++++++++++++++++++++++++++++++++++++++
**
*Material, Name=S235
*Density
1000
*Elastic
210000000000, 0.28
*Expansion, Zero=20
1.1E-05
*Conductivity
14
*Specific heat
440
**
** Sections ++++++++++++++++++++++++++++++++++++++++++++++++
**
*Solid section, Elset=Internal_Selection-1_Solid_Section-1, Material=S235
**
** Pre-tension sections ++++++++++++++++++++++++++++++++++++
**
**
** Constraints +++++++++++++++++++++++++++++++++++++++++++++
**
**
** Surface interactions ++++++++++++++++++++++++++++++++++++
**
*Surface interaction, Name=Surface_Interaction-1
*Surface behavior, Pressure-overclosure=Hard
**
** Contact pairs +++++++++++++++++++++++++++++++++++++++++++
**
*Contact pair, Interaction=Surface_Interaction-1, Type=Mortar
Surface-Slave, Surface-MAster
**Contact pair, Interaction=Surface_Interaction-1, Type=Surface to surface
**Surface-Slave, Surface-MAster
**
** Amplitudes ++++++++++++++++++++++++++++++++++++++++++++++
**
*Amplitude, Name=Tabular-1
0, 0, 1, 1
*Amplitude, Name=Tabular-2
0, 1, 10, 1
**
** Initial conditions ++++++++++++++++++++++++++++++++++++++
**
**
** Steps +++++++++++++++++++++++++++++++++++++++++++++++++++
**
**
** Step-1 ++++++++++++++++++++++++++++++++++++++++++++++++++
**
*Step, Nlgeom, Inc=1000
*Static, Solver=Pardiso
0.0001, 1, 1E-05, 0.005
**
** Controls ++++++++++++++++++++++++++++++++++++++++++++++++
**
**
** Output frequency ++++++++++++++++++++++++++++++++++++++++
**
*Output, Frequency=1
**
** Boundary conditions +++++++++++++++++++++++++++++++++++++
**
*Boundary, op=New
** Name: Displacement_Rotation-1
*Boundary
Node_Set-y, 2, 2, 0
** Name: Displacement_Rotation-2
*Boundary, Amplitude=Tabular-1
Node_Set-X, 1, 1, 11.46
** Name: Displacement_Rotation-3
*Boundary
Internal-1_Rigi-Z, 3, 3, 0
** Name: Displacement_Rotation-4
*Boundary
Internal-1_Rigi-Y, 2, 2, 0
** Name: Displacement_Rotation-5
*Boundary
Internal-1_Rigi-X, 1, 1, 0
**
** Loads +++++++++++++++++++++++++++++++++++++++++++++++++++
**
*Cload, op=New
*Dload, op=New
** Name: Surface_Traction-1: Deactivated
** Name: Gravity-1
*Dload, Amplitude=Tabular-2
Internal_Selection-1_Gravity-1, Grav, 10, 0, 0, -1
** Name: Uniform_Pressure-1: Deactivated
**
** Defined fields ++++++++++++++++++++++++++++++++++++++++++
**
**
** History outputs +++++++++++++++++++++++++++++++++++++++++
**
*Contact print, Totals=Only, Master=Surface-MAster, Slave=Surface-Slave
CDIS, CSTR, CELS, CNUM, CF
**
** Field outputs +++++++++++++++++++++++++++++++++++++++++++
**
*Node file
RF, U
*El file
S, E, ENER, NOE
*Contact file
CDIS, CSTR, PCON
**
** End step ++++++++++++++++++++++++++++++++++++++++++++++++
**
*End step

[fgr]

@Disla , I’m only able to run the mortar example with CCX_2.20 & CCX_2.21, so I would like to ask, which version of CCX have you been used for the mortar example ?

[Disla]

Solved with CCX_2.21.

With CCx 2.22 fails.

 *ERROR: increment size smaller than minimum
 best solution and residuals are in the frd file



Process elapsed time:       0.256 s

[fgr]

In the logbook for CCX_2.22 a lot of work have been reported about the mortar contact, maybe not all have been for the better.