Study on the Vibration of Bulk Carrier

在散货船顶侧舱测得剧烈振动的报道有几篇。为了研究这些振动，将船舶分为主船体、底部和顶部侧舱，并计算了这些结构之间的耦合振动。该方法将主船体、底侧舱和顶侧舱分别表示为简支梁、正交异性板和弯扭梁。通过计算结果与实验结果的对比，验证了该计算方法的准确性。但由于没有计算出实船所见的剧烈振动，因此认为顶侧舱的建模是不恰当的。在此基础上，提出了一种考虑横截面变形的弹性薄壁梁振动计算方法。考虑顶舱横截面变形的影响，对实船进行了振动计算，得到了顶舱振动占优势的固有振动。

There are several report in which the Violent vibration was measured at the top side tank of bulk carrier. In order to investigate these vibration, the ship was divided into the main bull, bottom and top side tank, and the coupled vibration among these structures was calculated. In this method, the main hull, bottom and top side tank were expressed as the Timoshenko-beam, orthotropic plate and bending-torsional beam respectively. The accuracy of this calculation method was confirmed by the comparison between the calculated and the experimental results. But the violent vibration which was seen on actual ship was not calculated.For this reason, it was considered that the modeling of top side tank is not proper. Then, a method to calculate the vibration of the thin walled elastic beam like the top side tank was proposed, in which the deformation of cross section was considered. The vibration of actual ship was calculated considering deformation effect of cross section of top side tank, and the natural vibration at which the vibration of top side tank becom dominant was obtained.