Bending About the Z Axis

The equations relating to the moment generated in a beam type spring element and the beam's displacement, (Figure 1) is given by:(1)
M z 1 = f z z ( θ z ) + C z z θ ˙ z
(2)
M z 2 = − M z 1

Where,

θ z = θ z 2 − θ z 1 is the relative rotation of node 1 and 2.

f z z ( θ z ) is the function defining the force-displacement relationship.


Figure 1. Bending about Z Axis