Failure due to nega...
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[Solved] Failure due to negative volume


Joined: 4 months ago
Posts: 6
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Hi everyone, i have issue with some contacts. I'm modelling a batterycell built by different components(Electrodes, Separators, ShellCasing ecc.) and i used SOLID elements. The separators and the active materials coating the electrodes are modelled with the CRUSHABLE FOAM MATERIAL MODEL (63) and i have introduced the ADD_EROSION for the separators. Because i have used the ADD_EROSION i have used also the ERODING_SURFACE_TO_SURFACE CONTACT between the separators and the other parts in contact, while i modelled the contacts between the other parts using AUTOMATIC_SURFACE_TO_SURFACE CONTACT. During the simulation i got the errore "failure due to negative volume". The strange thing is that if i run the simulation excluding the EROSION_SURFACE_TO_SURFACE and using the SURFACE_TO_SURFACE CONTACT the simulation finishes and i dont get errors. How is it possibile? Negative volume errors are related to large deformations and so i should get the error in both case. Until now i tried to use the following tips found on internet:

1) Used optional card B of CONTACT to turn shooting node logic off for contacts involving foam;

2) Increased the damping coefficient to 0.5 in the CRUSHABLE FOAM CARD;

But i couldnt obtain a good result and the same error always appeared.

What can i do? I leave here the .k file in case you would check. Thanks and greetings from italy.