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