Discussion Forum

I saw in document that slave boundary cannot penetrate master boundary, but it does.

hmmmmm....

I have not looked at your model. Have you set up contact pairs ? Of course, to do that, each part in contact must be part of an assembly of parts rather than a union (default) in the final step of the geometry creation. Then, the contacts will not cross boundaries. It also becomes much more difficult, and tricky, to solve; but, it does work quite well.

I did. There is contact pair and they are part of assembly.
I looked at forum and example files a lot, and I think I did everything I am supposed to do.

I think the contact boundaries should be only the 2 top surfaces, not the lateral faces of block number 1

When I don't include lateral faces, penetration occurs.

Do you have any ideas besides contact boundaries?

Hi Jay,

I noticed that the 7 m/s velocity you applied is too high. It is much higher than the wave speed through the lower block (around 3 m/s). Probably Young’s modulus for that block (9 kPa) is incorrect.

Nagi Elabbasi
Veryst Engineering

There are some general problems with your model.
1) Lateral faces are not contact surfaces, so you don't have to include them.

2) Mesh in contact models is always a problems. I'd use a swept mesh + boundary layer to have finer mesh where it is needed (at least in destination boundaries only). A coarser mesh can cause numerical problems at contact boundaries

3) Too high prescribed velocity, try to reduce it. I can't try to solve your model right now, so i can't say if this is enough or if there are other problems

A question, why simmetry in 2 later faces?

Try also to use identity pair under "Geometry form assembly" and contact pair under "definitions" (I never really understood the difference between this solution and contact pair under "Geometry, form assembly" + contact pair under "definitions", so perhaps it's a stupid suggestion)

Let me know if it works

Stefano

Try also to use identity pair under "Geometry form assembly" and contact pair under "definitions" (I never really understood the difference between this solution and contact pair under "Geometry, form assembly" + contact pair under "definitions", so perhaps it's a stupid suggestion)

The pair type that you select under "Geometry form assembly" is the type of pairs that will be automatically generated based on geometrical proximity. They will then appear as such under 'Definitions' where the type can be changed if necessary.

The idea is that you select a type under "Geometry form assembly" which is suitable for the majority of your pairs, and then switch the type of the others under Definitions. It is only the type a pair has under 'Definitions' which determines whether it can be used in 'Contact' in Solid Mechanics or not.

Regards,
Henrik

My results look like attached file.

Even if I decrease velocity, contact part is torn off.

Any one has a idea?