Learning Forum

[cct]

Hello,

I want to optimize a crash design in LS-OPT. We used to import IGES file to LS-PREPOST (as attached picture 1), but did not find out any way to define parameters (the distance between gaps and the offset of the gap). Thus, we tried to make the part in LS-PREPOST using offset in element edit tools. Its result (as attached picture 2) is not totally same as our original ones and I still do not find out the way to define the parameters.

I have some questions about these two:

1. Is there any other way I could do the offset more likely to my original ones?

2. I tried to use cfile to add parameters according to https://www.lsoptsupport.com/howtos/integrating-pre-processor/ls-prepost, but when I read the key file in LS-OPT, there is no parameter detected.

 

Regards,

Christine

[Ashish Khemka]

Hi Christine,

 

Is this a model for the bullet? Please let me know.

 

Regards,

Ashish Khemka

[cct]

Hi Ashish,

Sorry for the late reply. It's not a bullet model, but it is a simplified model for protect design of aircraft impact.

Regards,

Christine

[igandiko]

 

If you have a way of parameterizing depth and distance during CAD phase, note that you can use “user-defined” solver option in ls-opt to call any 3rd party solvers. You can use double bracket format <> to parameterize any field of input file and use them as variables in ls-opt. In this case , your ls-opt project can have three stages in series; CAD (modify geometry) > LSPP (mesh) > LS-DYNA (solver).

1.  If you want to stick to LSPP to modify the depth, please see here (https://ftp.lstc.com/anonymous/outgoing/imtiaz/ex_offset.mp4) for a potential option of creating requires grooves in the part. I don’t think there a direct option. Using depth as parameter is straighforward but I am not sure what would be the best way to parameterize spacing between grooves. Maybe you can first detach elements (pick them using “box” option), translate the elements, and then reattach disconnected regions. Maybe coordinates of the “box” can be parameterized. You will have to give it a try to see if this works.

2.  To define parameters in cfile, replace the field you want as a parameter with “&var_name” and add a line at top of cfile as below,

parameter var_name

 

[cct]

 

Hi Imtiaz Gandikota,

Sorry for the late reply. I will take a try with the ways you provide!

Thank you so much!

Regards,

Christine