I have a problem with an analysis with large displacements / strains in solution 601-106.
- isotropic material behaviour
- linear heaxeder elements
- symmetrical constraints for quarter modeling
- surface to surface contact
In my model I press a kind of stamp (solid) onto a solid plate with high pressure a I want to get it deformed in a very strong way with buckling and so on.
Everything works fine until I increase my pressure.
I 've got a distorted element in contact zone with large strains. The element penetrate itself with a strain of nearly 32 % compression. Otherwise the next element in vertical direction above contact zone shows a strain of positive tension in vertical direction.
Only the utmost element layer is compressed, the next is not. I expected that compression would procceed through element layers.
If I analyze other incrementation steps earlier, I could see that the effect is growing but not from the early beginning.
I've got the following error message:
Element distorted, Jacobian DET= -1.138862E-01 GROUP= 2 EL= 200830 MESH TOO DISTORTED (JACOBIAN DETERMINANT NOT POSITIVE) NUMBER OF ELEMENTS WITH NEGATIVE JACOBIAN DETERMINANT ...= 1 <<<<<<<<<<<<<<<<<<<<<<
And that is true.
Here some pictures:
1. Overlay plot of deformation during load incrementation (deformation scaling 1.00 absolute)
2. nonlinear strain component zz of compression zone of stamp (source region) at the end of aborted analysis:
Now my question:
Is this a limitation of solution 601 or may be an error in my model?
I' ve found a statement in help-documentation that acceptable maximum strains in solution 601 are nearby 30 %.
Is this limitation induced by such deformation effects or vice versa?
It looks for me as there is something like hourglass - deformation.
Does anybody know the internal relationships of NX and can help?
Could I change parameters for contact or NXSTRAT to improve the solution?