Contact dynamics of two floating cable-connected bodies

We consider two ship-like bodies connected by six cables and excited by waves. The cables might be under tension, or they might be slack, thus forming a unilateral system generating possible impacts. The impact forces can reach 20,000 kN and are able to cause damage to a ship. In order to avoid such large impact forces, anti-shock buffers might be adopted but good buffer design requires knowledge of the impact forces. We have evaluated these using multi-body theory with unilateral contacts in combination with classical ship dynamics, which allows modeling of the contact dynamics of two floating bodies in an ocean. Based on an optimization algorithm a method using an artificial neural network (NNW) has been developed to determine the combination of possible constraints at each step. The results of a numerical example compare reasonably well with experiments. We have thus established a theoretical basis for further buffer design.