Question on using SHELL181 elements 2

[nodalDOF]

I am trying to analyze a complex structure for basic loading conditions (need not be designed for plastic strains). The model is a surface and i am using SHELL181 elements for meshing. After meshing the surface i observed that some of my shell normals are facing other way (Ansys shows the mesh with blue and purple colors). I have imported this surface from solidworks.

My question is, is it necessary to rotate these normals before applying any loads/BCs? (So that all the surface that i think is top/bottom is of same color)

If so, is there any command to rotate these normals?

I have tried the following with no success
1. Specified a coordinate system (ESYS) before meshing.
2. Tried ESURF,,reve (That works for reversing the normals on contact elements)

any suggestions would be helpful (Hope my question is clear).

Thanks
NodalDOF.

 

[Stringmaker]

Nodal,
I believe that if you apply nodal BC's it shouldn't matter whether you delete and reapply them after reversing area or element normals. However, I would make all geometry modifications before applying loads or BC's if possible.

Shell element normals can be viewed with the /NORMAL command if your entire model is composed of shells. Otherwise, the easiest way is to plot element coordinate systems by issuing /PSYMB,ESYS,1.

Area normals can be modified by using the ANORM command. Element normals can be reversed by using the ENORM command. Note that you cannot flip area or element normals if surface or body loads are applied. Also, make certain that none of the real constants you have specified will be affected by your reversing the normals.

-Brian

 

[loom]

Have you tried areverse before meshing or anorm after meshing?

 

[nodalDOF]

Thanks to both of you! That solved my problem.

Nodal