Shell & Cable: Connectivity Issue?

Hello,

I’m studying a shell structure stabilized with cables. I scaled down the problem to a simple shell structure with pre-tensioned cables at the mid-section to better understand the problem. 

In the attached grasshopper, three models are developed: (1) a beam with a pre-tensioned cable, (2) a shell with the pre-tensioned cables, and (3) a simple shell.

In model (2), I made sure that the nodes of the cable are included in the shell membrane. The points of the shell attached to the shell move upwards significantly under the effect of the pre-tensioning of the cables suggesting an interaction between the shell and the cables. The cables also add significant stiffness seen in the increased buckling factor.

Before I deal with the peak stresses/deflection effect through "dummy" beams, the cables do not seem to deform or take any stresses as they do in the beam model (model 1). Is there a way to fix that?

Thank you for any help.

Best regards,

Mohamad