# Bending About the Y Axis

Where,

${\theta}_{y}={\theta}_{y2}-{\theta}_{y1}$ is the relative rotation of node 1 and 2.

Bending about the Y axis can be seen in Figure 1. The equations relating to the moments being produced are calculated
by:(1)
(2)

$${M}_{y1}={f}_{yy}\left({\theta}_{y}\right)+{C}_{yy}{\dot{\theta}}_{y}$$

$${M}_{y2}=-{M}_{y1}$$

Where,

${\theta}_{y}={\theta}_{y2}-{\theta}_{y1}$ is the relative rotation of node 1 and 2.

${f}_{yy}\left({\theta}_{y}\right)$
is the function defining the force-displacement
relationship.