Torsion

Torsional forces, shown in Figure 1, are calculated using the relations:(1)

M_{x 1} = f_{x x} (θ_{x}) + C_{x x} {\dot{θ}}_{x}

(2)

M_{x 2} = - M_{x 1}

Where,

$θ_{x} = θ_{x 2} - θ_{x 1}$ is the relative rotation of node 1 and 2.

f_{x x} (θ_{x})

is the function defining the force-displacement relationship.