FEMAP Help

[JuanAro]

I am working on the structural analysis of a spacecraft for a design project. I was imported the geometry onto FEMAP from SolidWorks. I encountered a problem when meshing my model. When I perform a modal analysis, the only part that seems to move is the bus structure. I have multiple interfaces connecting onto the bus structure and they do not react at all to the analysis. Any idea why? I was told that the structure was not connected properly by a colleague, but how do properly connect my structure?

JuanARO

 

[JuanAro]

Anyone please help on my FEM model. How do I properly connect my model??

 

[GruntCZ]

Try to check coincident nodes (tools - check - coincident nodes) , and then look to free edges (F5).

In the static analysis, the model behaves properly???

 

[rb1957]

"design project" = student post ?

Quando Omni Flunkus Moritati

 

[BlasMolero]

Dear Juan,
Check your mesh, if results not moving at all in some parts it means that the 3-D mesh is not exported to solver because is PLOT ONLY. EXPAND all menus under MODEL INFO TRESS and see if in MODEL > ELEMENTS > BY TYPE > "PLOT PLANAR", this means that your 3-D mesh was not performed properly.

Best regards,
Blas.

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

IBERISA
48011 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

Blog de FEMAP & NX Nastran:

http://iberisa.wordpress.com/

 

[JuanAro]

Thanks for the responses.

GruntCZ,
The model does work under static analysis. I have the spacecraft bus and on top of the bus are three mounted probes in a heatshield mounted on top of each other. In between each heatshield is a truss mount. I fixed the base of the bus, so now the bus does not move only the truss mounts (and not the heatshields, which are attached to the mounts). But the model produces zero errors in the static analysis.

BlasMolero,
I expanded all menus in my model info and this is what I have:
MODEL>ELEMENTS>BY TYPE> "I have BEAM,LINEAR and PLATE LINEAR"

Any help is greatly apprecieated.

JuanARO

 

[BlasMolero]

Dear Juan,
Post the FEMAP model here, or post any image, if not it will be difficult to know what happens exactly.
Best regards,
Blas.

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

IBERISA
48011 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

Blog de FEMAP & NX Nastran:

http://iberisa.wordpress.com/

 

[JuanAro]

BlasMolero,

I have attached a pic.

Thanks

 

[BlasMolero]

Dear Juan,
Well, whitout the model in hand is difficult to say anything based in the picture, upload the model and when available time I will take a look to it.
Best regards,
Blas.

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

IBERISA
48011 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

Blog de FEMAP & NX Nastran:

http://iberisa.wordpress.com/

 

[ThomasH]

Hi

You mentioned that a colleague had some ides regarding the connections. Why not ask him/her for help?

Based on your picture, the zero frequency often suggests some kind of rigid body movement. Animate the picture and see if anything moves that should not move.

Good Luck

Thomas