negative volume error lsdyna

[jaimitgandhi86]

I am trying to run my model without any boundary condition or forces (ie gravity, damping etc). I am getting error/warning message of "negative volume in solid element 123456 cycle 151 time= 9.815e-02" for hundreds of elements and I observe those elements get eroded. This is really confusing as I am not applying any forces or velocities in my model, yet elements are having negative volume. I tried to search the solution in number of portals but not able to run satisfactorily yet. I'll appreciate if someone has come through such a situation and suggest correction. FYI, I am getting this error in 10 noded tetras. I have improved element quality significantly but some how error keeps coming.

 

[jaimitgandhi86]

I am adding more details to my query above. I have observed that if I remove automatic_single_surface contacts from model than I am not getting the same error. Can anyone suggest, what might be the possible problem causing this negative volume?

 

[m2n037]

In simplest word, this means that the solid elements are compressed beyond limits. If you remove contact that means other elements will go inside the solid elements which is not a reality. You can try creating shell element coating over the solid elements like a cover with null material and negligible thickness. Then remove the solid elements from contact and add the shell cover in contact.

Hope this helps. Please let me know the result.

Regards,

Mukunda Madhava Nath
CAD/CAM/CAE Enthusiast