A steel wire cable with nonlinear properties can be modeled in Aqwa. Denoting as the asymptotic stiffness, as the asymptotic offset, as the initial unstretched mooring length, and as the attachment points on the two structures (in the fixed reference axes, where one structure may be a fixed location, for instance an anchor point), the tension on the steel wire cable is defined as

(9–19)

where

The names of the constants and arise from the fact that at large extensions, tends to unity and Equation 9–19 tends to the asymptotic form of

(9–20)