Gasket pretension analysis

Question

Hii everyone,

I want perform pretension analysis on gasket for checking sealing and gasket bulging when loaded.

Since gasket is non-linear I tried Radioss. I'm new to that. I tried copying RD-HM-T:1010 tutorial. It started confusing at start and at last I made something. Plates, gasket and bolts using 4 node tetra elements and Shank part of bolt as 1D srping elemnt.

For all components I used P14 solid and SPR_PRE and SPR_BEAM for pretension as per tutorial.

For all components except gasket I used LAW_2 Plas Jhons and for Gasket I used LAw_42 Ogden.

I used type 7 contact for friction contact we use GRNODE and SURF_EXT right. I did but when i tried running I got all the penetration  and Interface errors in groups. When isolated them i can only see arrow pointing in all direction. I tried searching online but no ref.

I even tried Inactive 5,6 no eff.

I del that contact and made a run, the stresses are above 500 M Pa and only at the shank region where that 1D beam contacts bolt. There's no effect on other clamped parts.

Somewhere something went wrong. please help me.

If possible pls gimme a file with the setup.

Thank you.

Mintu · Answer

In the RD-HM:1010, they used Type 24 Contact only by using SURF_id1(S), they didn't use SURF_id2(M).

I want to use TYPE 7 contact in that we have GRNOD_id and SURF_id, in GRNOD node I can only select a set with nodes, and SURF idon't know. I just created a set using create.

The thing is when I run the file, I am  getting penetration errors in the Contact just created. I can see penetration vectors in all directions.

In optistruct we have Master and Slave elements, we make a contact between them. Its simple.

So I tried repeating the same here, For GRNOD it used nodes of component A and For SURF I used SURF_EXT of component B. I'm getting penetration and Intersection errors.

Is the procedure correct, else please gimme step by step for creating TYPE 7 contact and removing penetration errors in contact.

I tried Altair learning, there's a tutorial using TYPE 7, but its Radioss V:2025.1 using SET GENERAL which I dont have in Radioss 2024

Guilherme_ · Answer

Hello.

Could you clarify which specific step you're looking for that isn't covered in RD-HM: 1010? Also, have you had a chance to check the Radioss e-learning? In the contact section, it covers all the details of TYPE7 contact (how to create, flags, exercises etc).

https://learn.altair.com/

Thanks,

Guilherme

Mintu · Answer

I can't share the files, I'm sorry.

I'm using Radioss 2024 Model, Can you make a simple pretension tutorial file and share with me.

If not please explain TYPE 7 set creation step by step procedure.

Thank you.