Learning Forum

[Tonmoy]

Hello Venkatesh,

If I understand correctly, you’ve specified a termination time of 0.05 seconds, which may not be enough to see the trend we are expecting. Though this isn’t my area of expertise and I didn’t do something like that before, I would suggest you to consider using *MAT_RIGID to model the structural steel. This would help reduce the solution time. Additionally, you could impose more boundary conditions on the model, particularly since we’re interested in the system’s behavior in the x-z plane. Therefore, we can constrain everything except for the X, Z and RY. The timestep size is generally determined by the CFL limit in LS-Dyna, and I don’t see changing it will improve anything in this case.

If I were you, I would initially start with a small amount of impact pressure, for example 1 psi or 5 psi, at the beginning of the simulation. I would then set the termination time in *CONTROL_TERMINATION to be very long, allowing enough time to observe the expected behavior. Once satisfied, I would gradually increase the impact pressure, starting from 10 psi, then 20 psi, and so on, sequentially.

This type of simulation is quite complex, involving both time and space considerations. Without any friction to reduce the velocity, the bullet might travel a significant distance, such as 5 or 10 km, before we can see the expected change. You can resort to MPP dyna or check if there is an alternative to do it (like changing initial condition or so).

 

With Regards, Tonmoy.