Geometrical responses from Optistruct

Altair Forum User

Hi,

 

I am trying to implement in an Optistruct optimisation a model that will help me to define a specific objective function I need for my work.

This model needs some plies geometrical information (for example, area and perimeter of each ply generated) as input in order to evaluate manufacturing cost related to the laminates at each iteration of the free-size optimisation.

 

I think I have two ways to do that:

1) to make Optistruct printing the .fem output file at each iteration and create an external script able to extract the geometrical parameters I need from the .fem file in order to calculate the external response (I will need DRESP3). The creation of this external script, extracting area and perimeter of the plies, does not seem to be so trivial.

2) to obtain the geometrical info inside Optistruct and create the response I need using DRESP2 along with equations internally created by myself.

 

I definitely prefer the choice 2) but the issue is that I do not have any idea on how to get these geometrical info as responses in Optistruct. I would greatly appreciate any help to solve this issue or any suggestion on the script creation to solve the problem following the choice 1).

 

Thank you in advance for any support.

Alessandro

 

Altair Forum User

Hi @Alessandro

 

I am wandering how to calculate area and perimeter using the internal responses via DRESP2. I will check and update you on the same ASAP!

Altair Forum User

Hi @Prakash Pagadala,

 

thank you for your reply.

I tried to look on the internet but I didn't find any similar problem. Having this kind of information could also help in selecting ply shapes during the free-size optimization.

Have you found something that can be useful in getting these ply geometrical information?

 

Regards,

Alessandro

Altair Forum User

Hi Aleesandro,

 

Not yet, I will update you on the same ASAP.

Altair Forum User

Hi @Prakash Pagadala,

 

I have pondered on the issue and I think that is not possible to obtain these ply geometrical data as DRESP2 because Optistruct generates the ply bundle only when it creates the _sizing.#.fem file. Before that, Optistruct works only with the elements thickness distribution for each super-ply.

 

Consequently, I think the solution 1) is the only possible way to extract geometrical info:

1) to make Optistruct printing the .fem output file at each iteration and create an external script able to extract the geometrical parameters I need from the .fem file in order to calculate the external response (I will need DRESP3). The creation of this external script, extracting area and perimeter of the plies, does not seem to be so trivial.

 

About this procedure:

- do you know if it is possible to obtain the _sizing.#.fem file at each iteration?

- do you know if a script able to calculate plies area from .fem file is available (if able to calculate elements area, it could be then modified to sum areas of elements related to the same plies)?

 

Thank you in advance,

Alessandro

Altair Forum User

Altair Forum User said:

- do you know if it is possible to obtain the _sizing.#.fem file at each iteration?

 

Try this: http://www.altairuniversity.com/learning-hyperworks/tips-tricks/optistruct/optistruct-ttf-output-results-by-iteration/

 

Altair Forum User said:

do you know if a script able to calculate plies area from .fem file is available (if able to calculate elements area, it could be then modified to sum areas of elements related to the same plies)?

I will check and will update to you.

 

But there is a tool in Aerospace profile where it can export the optimized ply shapes to CAD. You may have to create a subroutine to take each iteration results and export the data.

Altair Forum User

Altair Forum User said:

Try this: http://www.altairuniversity.com/learning-hyperworks/tips-tricks/optistruct/optistruct-ttf-output-results-by-iteration/

 

This allows me to have output results (displacements, stresses, strains, ...) per each iteration after optimization run is complete.

However, what I would like to have is the  _sizing.#.fem file with ply bundles generated per each iteration and this is  unfortunately created only at the final iteration.

 

Thank you anyway for the support.

Alessandro

Altair Forum User

Aleesandro,

 

Try OUTPUT>>DESIGN>>ALL along with results.

Altair Forum User

Hi Prakash,

 

Thank you for your reply but this doesn't work.

I have found, instead, that you need manually to write the line 'OUTPUT,FSTOSZ,ALL' in the .fem input file (the optione 'ALL' is not available in Hypermesh interface) in order to get  the  _sizing.#.fem file at each iteration.

 

Now this part is solved.

Please let me know if  a script able to calculate plies area from .fem file is available (if able to calculate elements area, it could be then modified to sum areas of elements related to the same plies).

 

Regards,

Alessandro

Altair Forum User

Altair Forum User said:

Please let me know if  a script able to calculate plies area from .fem file is available (if able to calculate elements area, it could be then modified to sum areas of elements related to the same plies).

Hi Aleesandro,

 

There is no script available to get the area of elements as on now.