Problem with explicit fem with solid-structure interaction in ABAQUS 2

[Arturogdc90]

Hi all,

This is my first post, so please don't red flag me if I am doing anything bad. I hope I can contribute to the forum in the future with the knowledge I have (mainly abaqus explicit).

My problem right now is with a simulation of a tank truck, I am trying to replicate an experiment and see if numbers match between FEM and real world. I am using volume fraction tool to situate a 50% of the volume of the tank as water, the tank mesh was created using Hypermesh.

When I start the simulation it happens that big bubbles appears in some contact points between the water and the structure. I have uploaded to images of two simulations (one using 50% fill volumen starting still and another using just a big box of water that falls in the tank). I have tried with simpler cases before and they were really good, but maybe due to the increased surface covered now I am facing this problem.

Water Box:

https://www.dropbox.com/s/vtx8nakqaow89e9/Ingtips1Box.PNG

https://www.dropbox.com/s/j7zq5lesasokfuc/Ingtips2Box.PNG

https://www.dropbox.com/s/5dglzf1kmiqrvn9/Ingtips3Box.PNG

50% Fill Volume:

https://www.dropbox.com/s/0vun6m4yxa6ae2q/Ingtips3_50pc.PNG

https://www.dropbox.com/s/z4crh72au8rj14n/Ingtips1_50pc.PNG

https://www.dropbox.com/s/4352ytpejc7nf8c/Ingtips2_50pc.PNG

Tank structure:

https://www.dropbox.com/s/alny5mrfz9alpjh/TankStructure.PNG

I can upload the odb file if you think that it would be helpful.

Big thanks, hope someone can bring some light into this I have been stuck with this since some time ago.

 

[burningDiesel]

I didn't save the result last time and forgot to put the friction back. It's a miracle it worked, but should definitely be put, else you'll get the same problem again.

 

[Arturogdc90]

I have checked different properties for the materials and I have discovered that the steel density is the variable creating the initial problem (that's why the first file was working), when you increase the steel density by 100x everything works flawlessly but when you return to normal material properties the problem starts again.

I can't understand why this is happening, I just leave it here in case someone knows about it or someone faces the same problem again.