- #1

ghobbs

- 14

- 0

Hi

I have a problem in understanding the attached free body diagram problem.

I have a shaft that is pivoted at the top. Below the pivot is a magnetic bearing with a radial stiffness of 2600N/mm. I've modeled this as a springs in parallel. Below the bearing is a motor with a radial stiffness of 1200N/mm.

The problem is that I don't know how to model the motor. I've previously thought of it as springs in parallel, but that's not correct. The motor is in equilibrium when on axis, but as soon as it moves off axis it is radially attracted. It's almost like it's a spring with a negative force.

I'm trying to produce a free body diagram for this system. When I apply a force F at the bottom of the shaft I want to know the reaction forces and deflections at the pivot, bearing and motor.

Any thoughts? Thanks.

I have a problem in understanding the attached free body diagram problem.

I have a shaft that is pivoted at the top. Below the pivot is a magnetic bearing with a radial stiffness of 2600N/mm. I've modeled this as a springs in parallel. Below the bearing is a motor with a radial stiffness of 1200N/mm.

The problem is that I don't know how to model the motor. I've previously thought of it as springs in parallel, but that's not correct. The motor is in equilibrium when on axis, but as soon as it moves off axis it is radially attracted. It's almost like it's a spring with a negative force.

I'm trying to produce a free body diagram for this system. When I apply a force F at the bottom of the shaft I want to know the reaction forces and deflections at the pivot, bearing and motor.

Any thoughts? Thanks.