CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Main CFD Forum (http://www.cfd-online.com/Forums/main/)
-   -   FSI or what? (http://www.cfd-online.com/Forums/main/108324-fsi-what.html)

cfd seeker October 19, 2012 10:17

FSI or what?
 
I have a problem in hand to model a flying bullet impacting a plate. Velocity and weight of bullet is known. This thing can be modeled by using Fluent/Mechanical APDL or not? Is it a kind of FSI problem or what? Thanks
Regards

cfd seeker October 19, 2012 13:02

If any body know something then kindly comment please........

agd October 19, 2012 22:02

My first response would be no, at least not in the classical FSI sense. Once the bullet impacts the plate the aerodynamics are essentially inconsequential to (and thus decoupled from) the deformation of the bullet, unless you are considering the bullet fragmenting and it is desired to track the fragments. You could use CFD to determine the initial state of the bullet immediately prior to impact, but the impact event and the resulting deformation would seem to depend very little (at best ) on the aerodynamics, apart from the aforementioned particle tracking. At least that's my semi-informed opinion.

cfd seeker October 20, 2012 03:15

Quote:

Originally Posted by agd (Post 387605)
My first response would be no, at least not in the classical FSI sense. Once the bullet impacts the plate the aerodynamics are essentially inconsequential to (and thus decoupled from) the deformation of the bullet, unless you are considering the bullet fragmenting and it is desired to track the fragments. You could use CFD to determine the initial state of the bullet immediately prior to impact, but the impact event and the resulting deformation would seem to depend very little (at best ) on the aerodynamics, apart from the aforementioned particle tracking. At least that's my semi-informed opinion.

Thanks for your response. You mean to say that I should calculate trust force of bullet from cfd and then use this force to calculate deformations in Mechanical APDL?

agd October 20, 2012 12:58

If I were doing the simulation, I would use CFD to compute the flight of the bullet up to the moment of impact. At that moment you have the state of the bullet, i.e. position, velocity, acceleration. These would serve as inputs to the solid mechanics solver. I don't have experience with your particular software, however. Just lots of time spent doing coupled CFD-6DOF analyses.

sail October 23, 2012 19:02

it all depends on what you need and how much in detail you want to go.

assuming that you are interested on what happens on the plate, i would go for a first calculation using a nonlinear dynamic FEA analysis (i think that mechanical can do them) using a time varing impact force as a boundary condition.

if you need more accurate results, you'll probably need an explicit FEA software. LS-dyna comes to mind but there are more.

but crash simulations are not easy, and they take many years of study and tests to master.

i don't think thet cfd is the answer for your problem, unless you want to study something you havn't told (shaped chrges, maybe?)

cfd seeker October 24, 2012 11:32

Quote:

Originally Posted by sail (Post 388205)
it all depends on what you need and how much in detail you want to go.

assuming that you are interested on what happens on the plate, i would go for a first calculation using a nonlinear dynamic FEA analysis (i think that mechanical can do them) using a time varing impact force as a boundary condition.

if you need more accurate results, you'll probably need an explicit FEA software. LS-dyna comes to mind but there are more.

but crash simulations are not easy, and they take many years of study and tests to master.

i don't think thet cfd is the answer for your problem, unless you want to study something you havn't told (shaped chrges, maybe?)

Lately I learned that this problem can be solved using LS Dyna or Auto Dyne.....currently working on Auto Dyne


All times are GMT -4. The time now is 10:42.