Parametric modeling of main excitation sources on board vessels

Efficient analysis methods for predicting the vibro-acoustic behavior of vessels are important, especially during the early design stages. A prediction software tool can help to identify critical points in the ship design and to avoid costly rework subsequent to sea trials. Therefore, an approach based on numerical system-level simulation, to estimate noise, vibration and harshness performance during each step of the design process is proposed. This paper is focused on the development of numerical models of main excitation sources on board. Parametric excitation models for main engines and pumps as well as structural models for power trains and foundations are built up. The sources introduce excitation forces into the foundations or torsional moments into the power train. The overall simulation model is built up modular and contains structural submodels as well as excitation submodels. System-level simulations using Matlab/Simulink are performed and both stationary operational conditions and transient excitations, e.g. engine run-ups and misfiring, are simulated. The numerical results are presented and the accuracy of the model is evaluated by comparing numerical and experimental data.