Development of a design procedure for the prediction of structure-borne noise generated by the reciprocating machines installed on board ships

往复式机械是船舶振动和结构噪声的主要来源。往复式机械产生的低频和高频振动能量通过船舶结构传递到舱室甲板，降低了乘客的舒适度，增加了船员对噪声和振动的暴露。此外，通过舰船结构传递的振动能量转化为水下噪声，影响海军舰船的声学特征，增加了影响海洋生物的水下噪声污染。为了从船舶结构中隔离辐射源，发动机和辅助设备通常采用弹性安装。该方案将船舶结构的噪声和振动源解耦，降低了噪声和振动源传递给接收结构的振动能量。尽管这种解耦方法被广泛接受和使用，但解耦系统的合理设计及其实际应用却更为复杂。有效设计源和接收结构之间的耦合应考虑源、隔离系统和接收结构的动态特性以及这些部分之间的相互作用。迄今为止，船级社规则和国际标准为设计人员提供了有效的程序来设计往复式机械和接收结构之间的解耦，从动态的角度来看，仅在低频范围内。关于结构传播的噪声水平，没有有效的预测程序，也没有提供任何标准限制。本提案研究了一种新的设计程序的发展，用于预测船舶往复机械产生的结构噪声。这个程序将以数值模型和解析公式为基础。一个新的模型将在纪念大学创建。该模型将重现船用柴油机基础的典型结构，并将进行实验测试以验证数值模型和分析公式的有效性。在这项研究活动中将开发的设计工具针对船舶设计师和船舶顾问。使用这些工具，他们将能够在新船设计的早期阶段预测由往复式机械产生的结构噪声，并确定有效的解决方案来降低整体船上噪声水平。这将增加乘客的舒适度，减少船员暴露在危险的噪音水平，并允许海军舰艇的设计师控制船只的声学特征。

Reciprocating machines are prominent sources of vibration and structure-borne noise on board ships. The vibrational energy generated by reciprocating machines, in the low and high frequency range, is transmitted through ship structures to accommodation decks, decreasing the comfort level for passengers and increasing the exposure to noise and vibration of crewmembers. Moreover, the vibrational energy transmitted through ship structures translates into underwater noise, affecting the acoustic signature of navy ships and increasing the underwater noise pollution that affects sea life. In order to isolate the sources from ship structures, engines and auxiliary machines are usually resiliently mounted. This solution decouples the source of noise and vibration from ship structures and decreases the vibrational energy transmitted by the sources to the receiving structures. Even though this solution is widely accepted and used, a proper design of the decoupling system and its practical application is more complex. An effective design of the coupling between the source and the receiving structures should take into account the dynamic characteristics of the source, isolating system, and receiving structures, as well as the interactions among these parts. To date, classification society rules and international standards provide the designers with effective procedures for the design of the decoupling between reciprocating machines and receiving structures, in the dynamic point of view, solely in the low frequency range. Regarding the structure-borne noise level, no effective procedures are available for its prediction, nor are any standard limits provided. This proposal investigates the development of a new design procedure for the prediction of the structure-borne noise generated by reciprocating machines on ships. This procedure will be based on numerical models and analytical formulations. A new mock-up will be created at Memorial University. The mock-up will reproduce the typical structures of a marine diesel engine foundation and experimental tests will be carried out to validate the numerical models and the effectiveness of the analytical formulation. The design tools that will be developed in this research activity aim at ship designers and ship consultants. Using these tools, they will be able to predict the structure-borne noise generated by reciprocating machines in the early phases of the design of a new ship, identifying effective solutions to reduce the overall on-board noise level. This will increase the comfort for passengers, decrease the exposure of crewmembers to hazardous levels of noise, and allow the designers of navy ships to control the acoustic signature of the vessels.