In this case study you have established a system consisting of a float and a rope anchored to the seabed. The aim of this case study was to demonstrate how contact between the rope and seabed can be modelled with the use of spring type Displaced. When the rope approaches the defined maximum allowed displacement the spring stiffness increase.

The purpose of this case study was to demonstrate how the Displaced spring can be applied to render contact with the seabed. The demonstrated case only considers one spring dedicated to several nodes. The user can add several springs with different type of input-values to simulate seabed with varying depths.

It should be noted that, as for any other dynamic simulations, that applying too high values of stiffness in the spring, in combination with a small value for the allowed amount of displacement, can cause numerical challenges. The model can be too stiff and cause convergence issues. To find a good combination, try with different input-values.