Submodelling a region of big model with coarse mesh to a refined mesh

[smsarthak]

Hello everyone,

I am analyzing a big FE model (all shell elements) and want to refine mesh of only a very small part of that model. I would like to know as how is the best way to do it and to apply displacement vectors, etc., at the node locations.

Thanks

 

[rb1957]

I tried this many years ago ... don't remember success but ...

the coarse rid model will give you displacements at the nodes (Duh) ... I think the key is on the fine grid model enforce a linear variation of displacement (so the fine grids between the displaced coarse grids see their respective displacements. model a simple panel first ... uniform stress applied to the coarse grid, displacements onto the fine grid ... do you get the right stress ? then a linear varying stress, then a couple point loads (complex displacements), then you should be ok with your real model.

these days you might get the desired effect using RBEs around the perimeter.

of course you can always transition mesh the coarse grid model ... but that could have problems of it's own (surface loads ?)

another day in paradise, or is paradise one day closer ?

 

[BlasMolero]

Dear smsarthak,
Take a look to my blog of FEMAP & NX NASTRAN in the following address:

https://iberisa.wordpress.com/2014/06/18/femap-symposium-2014/

There you have a post titled "14.- Global/Local Modeling: Tools and Techniques" from Joe Brackin, Senior Software Engineer, Siemens PLM Software.

Global–Local Modeling is a general topic where results from a global/system or coarse model are applied as boundary conditions to a more refined model of a component or subsection of the global model.

Femap has implemented a tool under the "Model/Load/From Freebody" Menu to help make this process easier for the user.

The new tool allows the user to select source nodes in a global model freebody and target nodes in the local refined model. The tool then creates RBE3 connections in the local model to apply the freebody loads and automatically creates local model load cases from the selected global cases.

Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48004 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

Blog de FEMAP & NX Nastran:

http://iberisa.wordpress.com/