I finally got it. I had to fix the contacts and tweak the airbag setup. Thanks everyone!!
It is not perfect but close. My only issue is that for some reason my internal energy increases a bit after impact and then remains there. I would expect it to go down after impact.
Anyone here familiar...
@IceBreakerSours
I think I am close. I thought I got it to work but then I tweaked something and now the ram doesn't rebound unless I reduce its density. Do you know how to use the airbag simple pressure option? The tank is filed with liquid so after impact the internal pressure in the tank...
@IceBreakerSours
Revision: smp d R12-1081-gb2b2774cf7
Just saw your post@ 05:30. So your plot says the ram rebounds 12" after around 0.0125 sec?! The contact does work with high ram density. But at steel density it goes through the tank. ie. contact is ignored.
Thanks for taking the time to...
@swimfan
At 0.5 sec the velocity went from 211.2 in/sec to 211.02 in/sec. The ram has to slow down a bit more than that in 0.5 sec. My guess is that my material is wrong but I am not sure what.
I just have the report from that analysis. What info do you want? I have deformation plots...
@IceBreakersSours
I do not see any rebound. Please refer to my Y displacement plot for a node on the ram. Maybe I am missing something. Also I did not notice any rebound during plot animation.
@IceBreakerSours
The results are very similar to plot @ 17:16.
I increased time to 0.5 sec and the ram kept on going. No rebound.
I have this feeling that the fix is something very trivial that I am missing. No reason for the ram to keep going. It has to stop and rebound a bit.
@IceBreakersSours
I ran your job. There was no movement at all. See plot below.
I have run multiple versions the same model. It is only when I run with the ram having a higher density that the deformation is good. At steel density the ram passes through the tank as the contact is not recognized.
@IceBreakerSours
Normals fixed. Not sure why it is fine in FEMAP but reverses in Dyna.
https://files.engineering.com/getfile.aspx?folder=94bfac8d-2212-4aad-a123-e52a97d1e587&file=impact.dyn
Hi All
I just realized that in plots @ 16:20 and 2:31 the ram doesn't really impact the tank. The contact doesn't work. It just goes through the shell a bit and retreats.
But for some reason when the ram density is increased contact is fine. See pic @ 17:16.
Merry Xmas guys!
@IceBreakerSours
This is how the analysis that I am trying to replicate was setup. In reality the tank (actually a tank car) will be on wheels.
Right now my concern is lack of deformation with rebound or lack of rebound with deformation.
Yes. Tank should look like pic @ 14:59 and ram should rebound as pic @ 16:20.
On another note, do you how to do a density scale factor? In the analysis I am trying to replicate, the ram and tank densities were scaled to get the right weight. I know I can adjust the material density to get the...
It appears that when I use the initial velocity the ram rebounds. But for some reason the tank is rigid.
Below plot is similar to the one @ 16:20 but run till 0.5 sec. You will notice that it has rebounded more than the 0.3 sec plot.
@rb1957
Yes. Ram is that tiny object. Tank is the cylinder.
Tank is regular steel.
Last pic is same at one before except time is 0.3 sec instead of 0.5 sec.
Still working on it. I do expect a rebound but I do not see any.
@rb1957
My bad. I guess the ram @ 0.3 sec was a different material. Below plot is the same at the 0.5 second but run till 0.3 sec. Either way initial velocity didn't change the behavior much.
@ rb1957
1st plot is with rigid ram. 2nd plot is with more denser ram to speed up the run. Tank is the same. I will run the 2nd case to 0.3 sec and see what I get.
I use student version to learn at home. We dont get a laptop.
FYI, I use FEMAP to setup and DYNA solver.
@rb1957
This is my plot with initial velocity. The ram appears to rebound after barely touching the tank. Now if I could merge the 1st plot deformation with 2nd plot rebound I would be on track.
