Tension

The tension component of the beam type spring element is independent of other forces. It is shown in 図 1. The tension at each node is computed by:

$$F_{x1}=f_x\left(u_x\right)+C_x{\dot{u}}_x$$

$$F_{x2}=-F_{x1}$$

Where,

$u_x=u_{x2}-u_{x1}$

Relative displacement of nodes 1 and 2

$f_x\left(u_x\right)$

Function defining the force-displacement relationship

It can be linear or nonlinear (Linear Spring to Nonlinear Elasto-plastic Spring: Decoupled Hardening).