MODAL RESPONSE OF CABINS AT LOW FREQUENCIES IN A RO-PAX VESSEL

Onboard ship noise represents a complex issue due to the interaction of different contributions such as engines, propellers, HVAC systems, and several propagation pathways throughout the ship structure from these sources to the various occupied spaces. Resonances can occur and strongly affect the acoustical comfort into closed spaces, particularly into cabins used to rest by the crew or passengers. Four different cabin geometries from a real passenger vessel have been simulated using 3D FEM techniques in order to obtain the modal response of each enclosure at low frequencies. The density of the modal frequencies was obtained for each space. Some of those frequencies could cause annoyance and could be caused by the engines or the propellers of the ship. The presence of high acoustic pressure zones in sensible locations of the cabins is evident in all the considered geometries. This approach can represent a valuable tool at design or retrofitting stages to achieve the best possible comfort levels by adopting control measures depending on each cabin geometry.