https://github.com/jfriedlein/ls-opt_parameter-identification
Some basics, settings and files for the straightforward use of LS-Opt for parameter identifications
https://github.com/jfriedlein/ls-opt_parameter-identification
ls-dyna ls-opt parameter-identification
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Some basics, settings and files for the straightforward use of LS-Opt for parameter identifications
- Host: GitHub
- URL: https://github.com/jfriedlein/ls-opt_parameter-identification
- Owner: jfriedlein
- Created: 2020-07-30T18:44:07.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2021-03-19T17:32:16.000Z (about 5 years ago)
- Last Synced: 2025-03-01T09:46:30.079Z (over 1 year ago)
- Topics: ls-dyna, ls-opt, parameter-identification
- Homepage:
- Size: 2.93 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# LS-Opt_parameter-identification
Some basics, settings and files for the straightforward use of LS-Opt for parameter identifications
## Setup of parameters
That's a bit tricky and best done in the .k-files via a text editor (that is not the best way to do it, nor the only, it is just how I do it).
For instance:
```
*PARAMETER
$# prmr1 val1 prmr2 val2 prmr3 val3 prmr4 val4
R K_AW 100.001
R sigy_AW 149.251
R Rincr_AW390.500
R omega_AW71.3325
```
The leading "R " indicates a "real" data type, so a floating point number. Alternatively, you could use "I " for integers.
IMPORTANT:
The parameters need to be defined in the .k-file that is directly input into LS-Opt under "Stage"->"Input File" and at a first glance cannot be outsourced and loaded via an "include" from a different file.
In material cards the parameters are used as:
```
*MAT_USER_DEFINED_MATERIAL_MODELS_TITLE
UMAT44-Alu
$# mid ro mt lmc nhv iortho ibulk ig
442.70000E-9 44 16 44 0 1 2
$# ivect ifail itherm ihyper ieos lmca unused unused
0 0 0 1 0 0
$# p1 p2 p3 p4 p5 p6 p7 p8
49953.36 23507.46&k_aw &sigy_aw &rincr_aw &omega_aw 1 3
$# p1 p2 p3 p4 p5 p6 p7 p8
0 1.25 0.75 1 0.4 0.4 0.4 0
```
So, entered at the left-hand side of the field with a leading "&" sign, as for parameter p3 "&k_aw ". Note that capitalisation does not matter at all ("k_aw" = "K_AW", inspired by Fortran).
## Setup of coupled optimisation
@todo Outline here how to obtain parameters that fit multiple simulations at once.
## Workarounds
* Don't use any special characters in the filename of the experimental data, so no "tensile test - steel - 0°.txt" (The degree symbol "°" generates error "exceed range").
* If you set up all the binouts correctly, but LS-Opt still complains that it cannot find them: Then deactivate the LS-Opt check of the binout files. In the stage card -> setup "LS-Dyna Advanced options" -> "Do Basic Check for Missing *DATABASE Cards" (deactivate)
* Always back-up your k-files especially when you use parameters (&...) in the cards. Sometimes LS-PrePost reads outcommented cards in, checks them for errors and writes them messed up back into the k-file even though you have not changed a thing in this card (remember you used *COMMENT for that reason).