Real variability in ship systems' noise and vibration Design and through-life management implications for underwater noise and habitability

摘要

Customers require completed ships to achieve acoustic performance relating to military stealth, standards for crew and passenger habitability and legislation for environmental protection. Design activity derives equipment and system specifications for machines, distributed systems and isolation treatments, since the whole ship performance achievability and sustainability relates directly to component noises and vibrations. The paper examines databases, compiled over many years, during noise rangings and supporting vibration surveys, for several ship classes. The databases allow for objective study of the statistical variability evident in a sample of typical machinery source mechanisms that relate to specific measures of performance. The evidence provides important findings. Critically, very significant variability exists in real underwater noise performance and the related vibrations when compared to median measurements and fixed targets. Technical and cost implications of this observation should be considered by initial ship designs or update programmes, where multiple systems and related mechanisms co-exist. Authorities planning condition based maintenance for system availability and the through-life management of onboard habitability or underwater noise are also encouraged to study the predicted or evidential behaviours using such an approach. Stakeholders in different disciplines should expect mutual benefits. Surveying is recommended, typically using available populations of systems on ships in-service.