Roadmap for Subcase Specific Modeling [OptiStruct]?

oldninja

Subcase-specific modeling is currently only available for linear analyses (2021 OptiStruct help). What is the roadmap for the implementation of the nonlinear and contact analyses?

Adriano_Koga

hi @oldninja 

 

can you be a little bit more specific on what do you need?

For NL there is MODCHANGE that covers a little bit these model changes from one case to another.

But it would be helpful if you describe some use cases too.

oldninja

Hi @Adriano A. Koga, 

Sure. We have a model with contact between parts and we are interested in performing some geometrical changes as well as some mesh refinements without the need to re-run the entire model due to its size. SUBMODEL, SID, SID_r<br />or<br />GLOBSUB, SUBID, SID

Are limited for the linear analyses, and we are interested in nonlinear with contact support. I read in a previous post (from a couple of years ago) that the development team was working on implementing these for other analysis types, so that is why I am asking for the roadmap to implementation.

I just searched for MODCHANGE in the OptiStruct documentation, so maybe let's add a request for documentation of that option if possible.

Thanks!

Adriano_Koga

oldninja said:

Hi @Adriano A. Koga, 

Sure. We have a model with contact between parts and we are interested in performing some geometrical changes as well as some mesh refinements without the need to re-run the entire model due to its size. SUBMODEL, SID, SID_r<br />or<br />GLOBSUB, SUBID, SID

Are limited for the linear analyses, and we are interested in nonlinear with contact support. I read in a previous post (from a couple of years ago) that the development team was working on implementing these for other analysis types, so that is why I am asking for the roadmap to implementation.

I just searched for MODCHANGE in the OptiStruct documentation, so maybe let's add a request for documentation of that option if possible.

Thanks!

sorry..my bad. It is MODCHG for changing NL models;

 

have you tried the newer submodel techniques?

I've tried myself creating a submodel from a lerger NL run, and it was fine.

I've never used NL to NL, but I believe it works too, as long as your local model doesn't affect too much your global stiffness.

https://community.altair.com/community?id=community_blog&sys_id=f3ba978ddbe86050e8863978f4961968

MODCHG

Bulk Data EntryDefines parameters for removing and/or reactivating contact interfaces and/or elements.

oldninja

Adriano A. Koga_21884 said:

sorry..my bad. It is MODCHG for changing NL models;

 

have you tried the newer submodel techniques?

I've tried myself creating a submodel from a lerger NL run, and it was fine.

I've never used NL to NL, but I believe it works too, as long as your local model doesn't affect too much your global stiffness.

https://community.altair.com/community?id=community_blog&sys_id=f3ba978ddbe86050e8863978f4961968

MODCHG

Bulk Data EntryDefines parameters for removing and/or reactivating contact interfaces and/or elements.

Thanks, I will look at MODCHG to see if it works for our purpose.

I haven't tested the newer submodel techniques. I read the manual, and it says that it is restricted to linear analyses; that's where I stopped. I looked at that beam model in the blog, but I have a more complex situation, but it certainly illustrates the option. 

What would be the workflow or a sample procedure using the MODCHG and SUBMODEL? Nonlinear and contact case.

Can I for example perform the global analysis with contact and nonlinearities and then perform the submodel as a linear case? 

Adriano_Koga

oldninja said:

Thanks, I will look at MODCHG to see if it works for our purpose.

I haven't tested the newer submodel techniques. I read the manual, and it says that it is restricted to linear analyses; that's where I stopped. I looked at that beam model in the blog, but I have a more complex situation, but it certainly illustrates the option. 

What would be the workflow or a sample procedure using the MODCHG and SUBMODEL? Nonlinear and contact case.

Can I for example perform the global analysis with contact and nonlinearities and then perform the submodel as a linear case? 

yes, you can perform NL global, and linear submodel.

I just did this to a submodel for a project. Of course, my submodel was built in a non-contacting area.