Studies on Methods of Calculating Accurate Natural Frequencies of Vertical Vibration of Ships

为了准确估算船舶垂向振动的固有频率，需要考虑船体与船底结构、甲板安装等大型局部结构的耦合振动的影响，对具有两块舷侧板、两块横隔板和一块船底板的单舱模型进行了垂向振动试验，并对底部结构的振动特性进行了研究。考虑到具有弹性底部结构的船体的耦合振动效应，对船舶的垂向振动进行了理论研究，并通过船模在水中的振动试验进行了验证，还对不同尺寸甲板翘度的船模进行了垂向振动试验。从理论上考虑了船体与甲板安装耦合振动的影响。理论计算结果与实验结果吻合较好。

In order to estimate accurately the natural frequencies of vertical vibration of ships, it is necessary to consider the effect of coupled vibration of ship hull and the large local structures such as bottom structure and deck errection.Vertical vibration experiments were made on single-hold models having two side shell plates, two transverse bulkhead plates and a bottom shell plate, and the vibration characteristic of the bottom structure was investigated. Taking into account the effect of coupled vibration of ship hull with elastic bottom structure, the vertical vibration of a ship was studied theoretically and the results were verified by vibration tests of model ships in water.Vertical vibration experiments were also made on model ships having deck errections of various size. Theoretical consideration was made on the effect of coupled vibration of ship hull and deck errection. Theoretical results showed good agreement with the experimental results.