2d analysis of a 3d model, not recognized (ANSYS R 15)

[Arnaud2]

Hello
I have imported 2 parts as assembly (step file)
In Ansys design modeler, I made a 2D model of that.
I want to define plane strain, so I do:
1) “Outline” pane > Model > Geometry
2) “Details” pane > Definition > 2D Behavior > “Plane Strain”
Step 2 does not show me the option for 2D behavior. Even though I already defined the properties of geometry as 2D.

Do you know what is the problem?

Thanks

 

[L_K]

Are all the surface bodies in the xy plane? Although in that case I think you should not even be able to import the bodies to Mechanical.

http://imgur.com/a/wTqnY

 

[L_K]

Try generating a whole new static structural module, then first switching analysis type to 2d and then start creating the geometry in DM.