Bending is related to a TORQUE and not to a FORCE. If you want to formulate it correctly you should ask for the bending torque. As soon as the elastic limit has been reached the torque is not very much depending on the angle. So that you not give the mechanical properties of the tube no one can give you an answer.
In general a question can be aswered when it is correctly formulated.
Bending Force calculation
Re: Bending Force calculation
