Learning Forum

[sqslh]

Hello,

I am investigating an output-mapping and energy-conservation issue in an academic civil/mining solver-verification unit test. This is not a weapon or defence model.

Environment:

• Ansys LS-DYNA Student, Windows x64

• SMP double precision R16.1-180-gd50332dbe5, one thread

• Units: mm-ms-g-N-MPa

• 2D axisymmetric S-ALE, 12,423 cells

• 808 cells initially filled with EMULSION

• *MAT_HIGH_EXPLOSIVE_BURN (MAT_008, BETA=0) with *EOS_JWL

• NEIPH=4, D3SALE=0, DMPMSH=1

• Termination time: 0.100 ms

I compared two input decks that are identical except for the lighting time LT in *INITIAL_DETONATION:

1. v3: LT=0.0 ms
   Normal termination, but the maximum absolute total-energy drift calculated from all original GLSTAT states is 15.995852%.

2. E2: LT=0.200 ms, after the 0.100 ms termination time
   Normal termination, and the maximum absolute total-energy drift is only 0.00049064%.

No interpolation, state deletion, filling, smoothing or renormalization was used.

However, I cannot yet prove from the original output that burn fraction F remained zero in all 808 explosive cells in E2. The binout contains only nine tracers, and the R16.1 manuals do not identify the exact full-field burn-fraction mapping for 2D axisymmetric S-ALE.

Could an LS-DYNA specialist please clarify:

1. With D3SALE=0, where exactly is the per-S-ALE-cell MAT_008/JWL burn fraction F stored in d3plot? Please identify the documented array/record location and the LS-PrePost Fcomp or Misc component.

2. With D3SALE=1, what is the corresponding LSDA path and array name in d3sale?

3. Is NEIPH=4 sufficient for full-field burn-fraction output for MAT_008 + EOS_JWL in 2D axisymmetric S-ALE? Does HISNOUT=3 provide valid labels for this field?

4. Are these output fields identical between the R16.1 Student and commercial executables?

5. Is the approximately 16% energy loss for LT=0, compared with approximately 0.00049% for LT=0.200 ms, a known R16.1 limitation, defect or energy-accounting behavior? Is there a recommended patch level, diagnostic output or control setting?

I am not claiming that the A/B comparison uniquely proves that burn, JWL or advection is the cause. I first need the officially supported full-field burn-fraction mapping.

Thank you.

[erik.kostson]

Hi

Ansys empl. can not provide feedback on this. Wait for other users to chime in.

All the best

Erko

[sqslh]

Thank you for clarifying, Erko. I understand and will wait to see whether other LS-DYNA users can share their experience.

All the best

[sqslh]

Additional controlled test completed: a 2× S‑ALE mesh refinement changed the maximum total-energy loss only from 1.58755% to 1.59180%. Mass conservation, geometry, stable timestep, GLSTAT component closure and material-account closure all pass. The loss is primarily associated with the EMULSION material.

Could anyone clarify two R16.1 output semantics questions?

1. Is Ekinlos an additive energy term that should be included in the global conservation balance?
2. Which supported database/output gives per-cell, per-material internal energy, kinetic energy and burn fraction for axisymmetric S‑ALE with *MAT_HIGH_EXPLOSIVE_BURN/JWL?

These definitions are needed before further numerical changes can be interpreted.