Learning Forum

[cct]

Hello,

We tried to use cfile to add parameters in LS-Dyna via LS-Prepost and run optimization in LS-OPT. Here is the flowchart in LS-OPT:

The parameters are detected and we set a continuous range for them:

However, we got same results in different points as the following figure, so we tried to run one of them manually in LS-Dyna and found the result is different from LS-OPT.

We are wondering wether the parameters are utilized well in LS-OPT. Does anyone face the same issue as ours?

[Imtiaz Gandikota]

It looks like you're running same model in all design samples. Please check if the solver is running correct input file with replaced parameter values. 

Please compare Lsprepost.inp (or similar name) in Stage/1.1 and Stage/1.2 and check if parameter values are different. This is the file that should be executed using ls-prepost.  You can also check if changing variable value changed the geometry or not by manually opening the input file using LSPP.

Similarly, if design variables are in lsdyna input file, you should check DynaOpt.inp file and this is the file that should be input to ls-dyna solver. 

[cct]

We used to check the input file created in stage/1.1, 1.2, and 1.3 using LSPP and found there is no any change. Yet in the lsopt_run_db.lsox, it shows the different parameter values (as following figure). Thus, we are confused whether the parameters apllied into LS-OPT well.

[Imtiaz Gandikota]

What command did you define in LSPP stage? Post a snapshot of LSPP stage and also show how you defined parameters in the cfile. 

Is there any difference in LsPrepostOpt.inp file in 1.1 and 1.2? This is the file LSPP runs to create new geometry. The input file defined in the stage is copied as LsPrepostOpt.inp to 1.1, 1.2, etc with parameter values replaced by ls-opt. 

You can also refer this example https://www.lsoptsupport.com/howtos/integrating-pre-processor/ls-prepost

[cct]

We set the directory of the LS-Prepost exe for the command in LSPP stage.

In the cfile, we define two parameters in the way as following figure:

In LsPrepostOpt.inp of 1.1 and 1.2, the values of parameters (the lighting parts) are different.