How to introduce *IMPERFECTION

[ArcadiaSolarSail]

Hi all, my Name is Daniele. I am an astronautics engineering student, I'm working on my master thesis program developing a new solar sail concept. Now I'm working on the sail membrane, in particular I'm working on the wrinkling problem. I read many papers of Prof. Sergio Pellegrino and Alexander Tessler , they worked on the same problem and used ABAQUS solver. I'm modelling this thin film with shell elements (S4), i need to introduce out-plane nodal imperfection following this formula z = alpha*thickness*randint(-1,1) where randint is a pseudorandomic function that give -1,1 or 0. This is important to allow the creation of the wrinkle, because if the thin film is perfect no out plane deformation will occur. My question is, how I introduce those imperfection? I read the pdf documentation and many of your forum posts, but always you give as simple the use of *IMPERFECTION option,I understood the theory and read many paper on this but how in Abaqus is possible to do? There is an option in the model three? I have to compile an imput file? And a lot of post talk about using the eigenvalues of buckle solution, but i need to use a direct value, as said in the Abaqus manual.
Sorry if the question can be stupid but this is my first project with abaqus and I'm learning it by me.

Thanks a lot
Best Regards

Daniele

Ps i work on abaqus/CAE 6.10

 

[ArcadiaSolarSail]

Anyone has an advice on this topic? Anyone has never used the *IMPERFECTION command?

thanks a lot

 

[ArcadiaSolarSail]

Hi to all

i tried to open an expample present in the solver folder, when i imported it the solver gave me this message:

WARNING: The following keywords/parameters are not yet supported by the input file reader:
---------------------------------------------------------------------------------
*ELFILE
*ELPRINT
*IMPERFECTION
*NODEFILE
*NODEPRINT

What's happening? The solver doesn't have the imperfection tool? Is possible?

best regards