Numerical simulation of the dynamic behaviour of resilient mounts for marine diesel engines

On board ships, to avoid high levels of structure-borne noise due to marine four strokes diesel engines, the latter are usually resiliently mounted. In order to improve the effectiveness of the decoupling between the diesel engines and the ship structures, it is important to have available tools and numerical models that simulate the dynamic behaviour of the isolator system as well as of the receiving structures. In the paper, after an introduction to the basics for the characterization of passive resilient mounts in high frequency range, an FE non-linear dynamic model of the isolator is presented. Such model takes into account the dynamics of the cast-iron parts, the contact between the top and base casting with the rubber core and the non-linear behaviour of the constitutive law of rubber. A procedure to achieve the characteristics parameters of rubbers is presented. The simulations have been then validated by experimental tests.