Learning Forum

[FluxLimited]

I've read over the section in the manual regarding the initialization of E0 for materials with Equations of State. I understand how to do it. But when is it critical to do so? I typically initialize v0 (initial specific volume) to 1.0. I have tried tests with materials and initializing E0 to rho*Cv*T or leaving it at zero does not seem to impact the simulation.

[Ram Gopisetti]

the internal enrgy is used where there is an thermal pressure and is dependent of volumetric compression and thermal state of an material.
Cheers, Ram

[FluxLimited]

thanks for your help. So if I am running a purely isothermal mechanical problem the value of E0 does not play a role? What about in the JWL EOS? There is no thermal component but I imagine the E0 would play a role in the energy density of explosives.

[Jim Day]

Yes, E0 would be nonzero in *EOS_JWL when modeling a high explosive.   Values may be hard to come by owing to the sensitive nature of modeling HE.

A fairly common application of E0 in *EOS is to initialize atmospheric pressure in air using *EOS_LINEAR_POLYNOMIAL.   Look for the notes on air in the LS-DYNA Aerospace Working Group MGD (Modeling Guidelines Document).  Use Google to locate this document.