BULLET IMPACTING A PLATE ISSUES

Question

Hi,

I'm trying to do a model of an 9 mm bullet impacting a laminate on RADIOSS.

I'm only using the lead core of the bullet with the LAW49 STEINBERG (Hyd_JHOOK and jonhson cook are also modeled). The laminate has got the law12 and is only a 3D block right now.

Therefore, i tried using Finite Element only, then SOL2SPH and finally SPH for modeling the bullet. The SPH model and a tetrahedric mesh model seems to work for the shape of the bullet but i would like to keep most of the solid with SOL2SPH or only with Finite Element. (There is also a rebond of the bullet that i don't want, is it because of this enormous simplification for the plate ?).

BULLET MODELS.zip

The issue is that i don't find a way to end the simulation, without having strains errors/ negative volume and distorsion of elements. I would like to keep a model with hexa element instead of tetra to also be more accurate.

Have you got any ideas of criterias or options i should use based on my model ? I would gladly have your help.

In the mean time, if i want to model the brass jacket of the bullet using sph modelisation, how can i deal with the interaction between both particules of the lead core and the jacket ?

Thank you for your help in advance !

Mathis · Answer

Hi @GLMT,

I had a look at your HM file. I had to correct a couple of things to make it running:

* I remove the option SPH_RESERVE from the PART Balle_SPH id 22. 
* I suppressed the /MAT/LAW4 as there was some input issues (missing rhoCp)

The model is running now. However, some elements are removed first cycle due to how the quality criteria are defined and how the bullet is meshed. I would recommand, as you are using a coarse mesh, to use a failure criteria to trigger the element erosion. /FAIL/TENSSTRAIN can be a easy candidate.

"In the mean time, if i want to model the brass jacket of the bullet

using sph modelisation, how can i deal with the interaction between both

particules of the lead core and the jacket ?"

SPH particles will see each other automatically. No specific treatment is necessary.

Regards,

Mathis.