Spring Members:
May be used as a truss member where the Longitudinal stiffness = AE/L

• A choice of almost any of the hysteresis rules available.
• Strength degradation is permitted for most hysteresis rules.
• Damage indices for the member may be computed for most hysteresis rules.

Ruaumoko:
Three actions (longitudinal displacement, transverse displacement and rotation about the out-of-plane axis, i.e. z-rotation)

1. No Interaction between longitudinal and transverse components.
2. Quadratic Interaction between longitudinal and transverse components (Tri-linear hysteresis only).
3. Degradation in the transverse stiffness is a function of the rotational spring ductility. (Used to represent shear-flexure interaction and shear strength degradation due to flexure)
4. A model where there is an interaction between the axial force in the spring member and the yield moment in bending about the z axis.

Ruaumoko3D:
Six actions (longitudinal displacement, two transverse displacements, twist and rotations about the two transverse axes)

1. No Interaction between longitudinal and transverse components.
2. Quadratic Interaction between longitudinal and transverse components.
3. Degradation of the transverse stiffnesses as a function of the rotational spring ductilities. (Used to represent shear-flexure interaction and shear strength degradation due to flexure)
4. A model where there is an interaction between the axial force in the spring member and the yield moments in bending about the y and z axes.