Sum of output block's internal energies doesn't match up total internal energy

Viktor Antevski
Viktor Antevski Altair Community Member
edited October 16 in Community Q&A

Hello,

I am running a welded steel structure in Radioss. I am interested in the separate energies of certain assemblies. I put them in separate output blocks. Than, in Hypergraph line chart I plot the internal energy of all the blocks and the sum of them is less than the global internal energy. I also added the spring internal and contact energy and still it doesn't account for the whole total energy. Hourglass energy is near zero. I am missing some 5 percent of the total energy.
I also have solver dt mass added of around 4% of total mass for the timestep. Is it that the solver doesn't take this mass into account when calculating internal energy of separate components?
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Thank you very much,
Viktor

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Answers

  • PaulAltair
    PaulAltair
    Altair Employee
    edited October 15

    Did you check hourglass energy at the part/assembly level? If you are using physical hourglass elements (QEPH/HEPH) then the energy for that is accounted for in Internal Energy at global level (Hence zero HG reported), but it is accounted for in Hourglass energy at part level.

  • Viktor Antevski
    Viktor Antevski Altair Community Member
    edited October 16

    Very well, how can I check the hourglass energy at part level? Using a curve for each output blocks? So does this mean, that the sum of the IE of the output blocks is the global internal energy minus the hourglass energy per part? Is the sum of the IE of output blocks the real physical energy I would get in my model?

    Thank you very much Paul,
    Viktor

  • PaulAltair
    PaulAltair
    Altair Employee

    Sort of, If you have requested /TH/PART, which you already have?, then the HE (HG energy at part level) should be visible?

    However, The output for HE for the QEPH/HEPH at part level is numerical damping rather than energy, so it still won't sum to the full values, but it should give you an indication if that is where the difference is coming from

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