Dynamic + Contact + Isotropic Hardening = No Convergence

1

CCX version 2.17 compiled for windows found at http://www.dhondt.de/calculix_2.17_4win.zip

I have also tested on older versions as well with the same results.

When I attempt to use a combination of Non-Linear Dynamic + Surface To Surface Contact + Isotropic/Kinematic Hardening, the solver exits without any error or output, all outputs files (dat, out, 12d, cvg, frd, and sta) are empty as well.

Sometimes instead of the solver exiting without error I will get this error repeatedly until the solver kills itself or I exit the solver:

*ERROR: no convergence in incplas

Did I overlook something? Is surface to surface contact not compatible with Dynamic+Isotropic/Kinematic Hardening?

Below is an input file I made to boil down the problem:

*NODE
1,0,-0.5,0
2,1,-0.5,0
3,1,0.5,0
4,0,0.5,0
5,0,-0.5,1
6,1,-0.5,1
7,1,0.5,1
8,0,0.5,1
9,0,0.51,0
10,1,0.51,0
11,1,1.51,0
12,0,1.51,0
13,0,0.51,1
14,1,0.51,1
15,1,1.51,1
16,0,1.51,1
*ELEMENT,TYPE=C3D8
1,2,6,7,3,1,5,8,4
2,10,9,13,14,11,12,16,15
*ELSET,ELSET=cube2
1
*ELSET,ELSET=cube1
2
*SURFACE,NAME=cube2Contact
2,S1
*SURFACE,NAME=cube1Contact
1,S5
*MATERIAL,NAME=464_Brass
*ELASTIC,TYPE=ISOTROPIC
99973980750.94,0.28
*DENSITY
8414.691031902
*PLASTIC,HARDENING=KINEMATIC
310264078.1926,0
345048128736.6,1000
*SOLID SECTION,ELSET=cube2,MATERIAL=464_Brass
*SOLID SECTION,ELSET=cube1,MATERIAL=464_Brass
*BOUNDARY
1,1,,0
1,2,,0
1,3,,0
2,1,,0
2,2,,0
2,3,,0
5,1,,0
5,2,,0
5,3,,0
6,1,,0
6,2,,0
6,3,,0
11,1,,0
11,2,,0
11,3,,0
12,1,,0
12,2,,0
12,3,,0
15,1,,0
15,2,,0
15,3,,0
16,1,,0
16,2,,0
16,3,,0
*AMPLITUDE,NAME=Aconstant
0,1
*CONTACT PAIR,INTERACTION=SI_1,TYPE=SURFACE TO SURFACE
cube2Contact,cube1Contact
*SURFACE INTERACTION,NAME=SI_1
*SURFACE BEHAVIOR,PRESSURE-OVERCLOSURE=LINEAR
99973980700
*STEP,NLGEOM=YES,INC=10000
*DYNAMIC
0.01,0.1,0,0
*NODE FILE,GLOBAL=YES
U
*EL FILE
S
*END STEP
2

Why don’t you have any:
*CLOAD
*DLOAD
*BOUNDARY

after *STEP?

4

rafal, my first reply to you got filtered as spam, so I will keep this reply all lower case and without asterisks.

The boundary is defined above step since it is homogenous. There are no loads applied to keep this example input file as simple as possible.

If you change to node to surface instead of surface to surface or delete the plastic card it will run and converge without any issues.

5

I’ve heard of this problem before. Dynamic + plastic + contact = crash. I think it’s a bug.

2 Likes
6

Can confirm this bug exists in 2.18 release.

1 Like
7

And in 2.19. I’ve tried a few variants (different element type, explicit, nlgeom off) but nothing helps. The only workaround so far is to switch to node to surface contact.

Maybe @dhondt could take a look at this in the future.

1 Like
8

Sorry for reusing an old post but I can’t find any other working example or progress about this subject.
I managed to make converge some models with Dynamic + Contact + Plasticity, but the PEEQ stress doesn’t respond properly. CCX Version 2.22
Equivalent plastic Strain increases up to a maximum value but later decreases once the projectile rebound. That’s not as expected.
Another conclusion is that I don’t think C3D8I is suitable for this combination.

imagen
imagen1497×868 34 KB

*NODE
1,0,0,0.103
2,0.1,0,0.103
3,-0.4310522938113,0,-0.0254
4,0,0.4310522938113,0
5,-0.4310522938113,0,0
6,0,-0.4310522938113,0
7,0,0.4310522938113,-0.0254
8,0.4310522938113,0,-0.0254
9,0,-0.4310522938113,-0.0254
10,0.4310522938113,0,0
11,0.1,0.1,0.103
12,0,0.1,0.103
13,0,0,0
14,0,-2.22044604925E-16,0
15,0,0,0.003
16,0.1,0,0.003
17,0.1,0.1,0.003
18,0,0.1,0.003
19,0,0,0.053
20,0,0.05,0.003
21,0,0.05,0.053
22,0,0.05,0.103
23,0,0.1,0.053
24,0.05,0,0.003
25,0.05,0,0.053
26,0.05,0,0.103
27,0.05,0.05,0.003
28,0.05,0.05,0.053
29,0.05,0.05,0.103
30,0.05,0.1,0.003
31,0.05,0.1,0.053
32,0.05,0.1,0.103
33,0.1,0,0.053
34,0.1,0.05,0.003
35,0.1,0.05,0.053
36,0.1,0.05,0.103
37,0.1,0.1,0.053
*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
*ELSET,ELSET=EALL
1
2
3
4
5
6
7
8
9
*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=BASE
*ELASTIC,TYPE=ISOTROPIC
100000000,0.3
*DENSITY
1167.860207
*SOLID SECTION,ELSET=BASE,MATERIAL=BASE
*BOUNDARY
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
*AMPLITUDE,NAME=AZ_1
0,0
0.002,-9.8
0.003,-9.8
1.6,-9.8
*DAMPING,ALPHA=0,BETA=1.3557E-05
*MATERIAL,NAME=STEEL
*ELASTIC,TYPE=ISOTROPIC
100E6,0.3
*DEFORMATION PLASTICITY
100E6,.3,0.1E6,12.,0.4
*DENSITY
7870
*SOLID SECTION,ELSET=Ball,MATERIAL=STEEL

*INITIAL CONDITIONS,TYPE=VELOCITY
N_Ball,1,0
N_Ball,2,0
N_Ball,3,-5.0

*CONTACT PAIR,INTERACTION=SI_2,TYPE=SURFACE TO SURFACE
SLAVE,DRUMS
*SURFACE INTERACTION,NAME=SI_2
*SURFACE BEHAVIOR,PRESSURE-OVERCLOSURE=HARD
*STEP,INC=1500,AMPLITUDE=STEP,NLGEOM=ON
*DYNAMIC,SOLVER=PARDISO,ALPHA=-0.01
0.001,0.025,0,0.001
*DLOAD
EALL,GRAV,0,1,0,0
*DLOAD
EALL,GRAV,0,0,1,0
*DLOAD,AMPLITUDE=AZ_1
EALL,GRAV,1,0,0,1
*NODE FILE,GLOBAL=YES
U,V
*EL FILE
ENER,S,NOE
*EL FILE
PEEQ
*Contact file
CDIS, CSTR
*END STEP
9

Hi,
I think you need node-to-surface contact for plasticity. I have read this some years ago.
Kindly regards
Markus

1 Like
10

Thanks for paying attention to this Markus.

The contact seems to respond properly. The unexpected response is that the model is recovering its initial shape after noticeable plastic deformation (>50%).
Equivalent plastic Strain is a cumulative and irreversible phenomena if I’m not wrong. The .inp is a reduced example that shows it in case someone has an explanation , I did something wrong or maybe others want to investigate to find the source.

Thanks again

EDITED: By the way, I forgot to comment that this inp file fails with ccx2.21 but converge with ccx 2.22. (PARDISO)

1 Like