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Honeycomb Impact Attenuator Issues

Hi everyone,

I keep getting 'WARNING ZERO OR NEGATIVE VOLUME' errors when I run my setup.

I have tried using default fscaling for the material curves because I was using different units than the tutorial but that would create a weird expanding behavior and still result in the same error. I based my setup off of the crashbox tutorial but it does't address or explain this.

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Radioss

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Pranav Hari

Hi /profile/99966-puffin/?do=hovercard&referrer=https%253A%252F%252Fforum.altair.com%252Ftopic%252F40633-honeycomb-impact-attenuator-issues%252F' href='<___base_url___>/profile/99966-puffin/' style='background-color:transparent;color:inherit;' title='Go to puffin's profile' rel=''>puffin

In General Negative Volume error happens when solid elements are very deformed and their characteristic length goes to 0. You can avoid this by switching to small strain formulations

Also check these previous forum posts about this topic

Still if you are not able to rectify it please share the .rad files

puffin

Hi Pranav,

I have started to look through the old posts about this error but I don't understand how Ismstr = 2 and ENG/DT/BRICK/CST work. Does it switch to small strain during the simulation?

Also I have tried running the simulation with Ismstr = 1 and it results in a energy error. Is this still something wrong with small strains or is it with my material properties?

Edit: I have found errors with the data I entered in and fixed it. It is now able to run but I am still uncertain if is correct. Here are the up to date files

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