how bend a sipmle tube

[cosoga]

Hello,
i want to bend a "3D cylinder surface element, by applying bending force or rotation Boundary conditions,

i constrained one base of the cylinder ( encastre bc)

I tried using coupling kinematic constraint on the surface of tube , applying UR= value on th reference node,

i didn't got the wanted results, ???

Any suggestion will be appropriated,

Regards,