Transfer-path analysis to estimate underwater radiated noise from onboard structure-borne sources

This work analyzes the modeling of structural noise sources on marine vessels to estimate the resulting underwater radiated noise. In particular, the focus is on the structure-borne noise generated by the ship's diesel engines because of their significant effect on the underwater noise signature of the vessel. The radiation of structure-borne noise underwater is represented using transfer-path analysis. The dynamic response of the machinery foundation is simulated experimentally using a scaled mock-up model. The model is then suspended above a water tank, and the underwater radiated noise levels are measured using fixed-positioned hydrophones. Then, the experimental data are used to validate the coupled numerical acoustic–structural analysis of the foundation suspended above the tank. Each component of the transfer path obtained experimentally and numerically is characterized separately and then combined to evaluate the underwater radiated noise. The presented methodology is an effective tool for ship designers for preliminary estimations of underwater radiated noise from onboard machinery and evaluating the effectiveness of mitigation solutions.