model high speed bullet using openradioss

[wanglei742]

i saw an animation using the CFD to model the bullet, so i believe the openradioss can also replicate this phenomenon. but I face some issues below, can anyone give me some cues or guidance? very much appreciated for this,pls see attached

the attached is the axisysm model and model size is very small, before running the attached pls change the .txt to .rad
bullet_0000.txt
bullet_0001.txt
Thanks

[RevolT87]

Hi @wanglei742,
This is indeed possible to do this kind of simulation using OpenRadioss. You need to use the multimaterial law 151. Here is an example of an air burst model:
https://community.altair.com/csm?id=altair_file_exchange_article_view&sysparm_article=KB0119695
You can use the 2D axi-symmetrical model as a source of insipiration.
Regards,
Mathis.

[Schwoertzig]

@wanglei742 ,
there is an old implementation of such sliding interface for : 3D staggered scheme and mono-material law only.
( https://help.altair.com/hwsolvers/rad/topics/solvers/rad/inter_type12_starter_r.htm#inter_type12_starter_r )
What would be interesting in your case (if precision is still not enough using all recommendations brought by @RevolT87 ) would be to introduce in source code compatibility with 2D, colocated scheme, and multimaterial.
Regards

[wanglei742]

Hi, Thanks to both, current methodology is enough for my simulation. i will try both of your advice

[wanglei742]

Hi, Schwoertzig:
hello again, I revisited your reply when i came across the solid/fluid prop
the previous reply"it's prudent to refrain from using /prop/fluid unless you specifically intend to deactivate pseudo viscosity in staggered schemes"
so my question is when I need to employ the fluid prop, i still confused about the this. here is a example link in the altair website
https://community.altair.com/community/en/mok-fluid-structure-interaction-fsi-benchmark-simulation-with-radioss?id=kb_article&sys_id=67a8910497554610e3b0361e6253afd7
you can visualize the mesh can move and deformed, is this reason the example use the solid fluid prop?
appreciated if you can reply

[Schwoertzig]

Hi @wanglei742
You never need to utilize /PROP/FLUID. You can simply disregard it. It's essentially a shortcut to /PROP/SOLID with qa=qb=0.0, which is not advisable.
Regards

[wanglei742]

Hi, Schwoertzig:
based on your reply, let me just forget this fluid prop.
very much thanks