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Non T-joints surfaces questons

Experimenter
Experimenter

Hello.

 

I am trying Femap since a month and I have questions about surfaces modelling. I am working with a solid model imported from an IGES file. The original model (image 1) was created with structural shape steel and steel plates and I am generating surfaces to get the solution faster. Actually, I generate surfaces in the structural shapes with the midsurface command to obtain I-shape like the solid model, and add them with the command "Non manifold add".

 

First question: If I try meshing I-shapes, I can select only half flanges (image 2) and the meshing process is not doing completely. What can I do to select the entire surfaces?

 

Second question: The model has coplanar sheet metal parts (image 3) doing contact between them and I want to create surfaces in this parts to complete the model preprocessing. How can I connect that parts where there are coplanar? 

 

I receive all sugestions because I really like femap but I don´t use it very well.

 

Thank you.

 

Miguel

1 REPLY

Re: Non T-joints surfaces questons

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Miguel,

In geometry problems like this FEMAP V11.1.2 is really powerful creating midsurfaces, but you need to do a request for a training class to your FEMAP reseller to learn how to do things correctly and became productive inmediately because FEMAP give you multiple ways & commands to do midsurfaces and novice users do not know how to star the job.

 

Also you need to understand the diferences between Sheet Body and Non-Manifold Body, and the advantages and limitations of both entities. For instance, surface T-Joints can only created using non-manifold command, but the resulting surface geometry can not be longer manipulated like perform a surface extend, surface normal reorient, etc.., then "Geometry > Surface > NonManifold Add .." command should be the very last command to issue.

 

From the other side, "Geometry > Solid > Stitch" is a great command, not only stitch multiple surfaces to form a sheet body, but also assure consistency in surface nomals, a key point when meshing with Shell elements for later postprocessing stress results in Top & Bottom faces of Plate elements. The limitation to this great command (well, Parasolid engine) are the T-Junctions, where only NonManifold-Add command is available. Hopefuly in the future we can use here the Stitch command as well, the Parasolid group is working harder with the FEMAP team to get results soon in this line ...

 

Without the FEMAP model in hand not too much to say, but take a look to this post in my blog where I explain how to perform midsurfacings and how to use GLUE contact:

http://iberisa.wordpress.com/2012/09/26/41-femap-midsurface-modeling-metodo-offset/

 

Creación de Superficies Medias en FEMAP para mallar con elementos Shell 2-D CQUAD4. También explico cómo definir contactos GLUE EDGE-TO-FACE y elementos rígidos RBE2. Enseño cómo usar el "Meshing Toolbox" para definir "PADs", partir superficies con "point-to-point", "point-to-edge" y "edge-to-edge", etc.. además de diferentes técnicas de mallado con elementos Shell tales como "Mapped - Three corner" a través de la orden "Meshing Approach"

 

You have available this video as well:

 

 

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/