Bullet Explicit Analysis

[Anonymous]

Hi,

I tried to replicate the impact of a bullet using the Explicit Analysis, unlikely without success.

I tried using the enforced velocity and constraining the bullet with the Rigid (Esplicit) constraint, thinking that I should constraint the direction of its motion. The analysis ends but with 0 displcement and 0 stress on every part.

I tried also using the classic constraint (not the Esplicit type) but without success.

When I tried to use the Explicit analysis on the Tutorial made on the Chain I obtained correct result...maybe in this example I miss something.

Could you help me to solve this problem?

thx

Luca

[Roelof.Feijen]

Hi Luca,

Don’t have the time now to look at your assembly. Will do that a.s.a.p.

Btw have you seen my video that more or less looks like the same analysis you try to perform?

https://autode.sk/39Ofr72 

[Roelof.Feijen · Accepted solution]

Hi Luca,

Finally had the time to look at your assembly.

Take a look at the screencast below on how to solve this.

[Anonymous]

Hi Roelof,

thx for your answer, I accepted it as solution because it is exactly the same case.

Despite this I found strange result when I model using the simmetry;

after the impact the bullet doesn't go straight but it starts turning in the simmetry plane...and this should't happen I think.

thx for your reply

Luca

[Anonymous]

Hi Roelof,

thx for the videos; I did it.

I added an extra step of difficulty with a series of plates and it works even in this case (video in attachment).

One final question: is it possible to make the bullet deformable? 

With the actual settings the bullet cannot deform. Is it mandatory to keep the bullet rigid?

thx

luca

[Roelof.Feijen]

Hi Luca,

Nice video 😀

You can uncheck the Rigid option in your material properties.

That should work to make it deformable.

Edit: You also need to replace the Rigid Motion. This video shows you how to setup without a Rigid Motion.

[Roelof.Feijen]

Hello Luca,

It's a lot of fun playing with these kind of assemblies and type of analyses.

See my assembly in the attachment. What I changed about the analysis is:

1. Material properties of Acciaio inox AISI 440C
   A. Disable rigid
   B. Turn on nonlinear - Elasto-Plastic
2. Under Impostazione dinamica 1 I have of course adjust the total time. This was based on the Initial Condition - Velocity and some trial and error. The Initial Velocity determines how many plates are penetrated. You need enough simulation time to see this happen.
3. Carico 1 changed to an Initial Condition - Velocity. Velocity value is also a little bit trial and error. The plate thickness, material properties and number of plates determine what is actually happening.
4. Vincolo 3 changed into a Structural Constraint. Just to make it stable in the y-direction.