Dear all,
Hi @csuznxg,
Are you experiencing this in a simulation? From what I know (which isn't much) negative strain energy isn't real and is a product of some numerical process in LS-Dyna. I think negative internal energy can be attributed to shell thinning or damping in Dyna? Have you looked through the below link?
https://www.dynasupport.com/howtos/general/internal-energy
@negativevolumeThank you. Yes, I encountered this in blasting simulation with FE in LS-DYNA. I checked that link and doesn't work for my model. I am using solid elements. I also saw some posts regarding this subject in Abaqus or Comosol Forum. It seems that this is a limitation in FE. The results are reliable but the negative strain energy should be treated as 0.
@csuznxg i’ve had the the same problem, negetive internal energy in ls-dyna. Then I adjusted the model, the result turned out to be normal. but i still don't understand why the negetive internal energy exist. have you solved it?
@douodou Not Yet. Could you tell me how to adjust the model?
@csuznxg I don't know which operation cause the right energy results 😰 . I didn't use the shell element, but used solid element and beam element,when the negative internal energy occurred. So the reason (in the above link) for negative internal energy in shell element cant account for my model.
@csuznxg i encountered the negative internal many times, when i was adjusting my model. but i cant find the reason for negative internal energy.
@douodouI am using solide elements and the internal energy is normal. Only strain energy in unloading area is nagetive.