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

1986 Fiscal Year Final Research Report Summary

• Project/Area Number: 60550306
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 船舶構造・建造
• Research Institution: Osaka University
• Principal Investigator: MATSUURA Yoshikazu Professor, Faculty of Engineering, Osaka University, 工学部, 教授 (00028945)
• Co-Investigator(Kenkyū-buntansha): HASHIMOTO Kiyoshi Assistant, Faculty of Engineering, Osaka University, 工学部, 助手 (50183554) ; FUNAKI Toshihiko Assoc. Prof., Faculty of Engineering, Osaka University, 工学部, 助教授 (90029174) ; TOMITA Yasumitsu Assoc. Prof., Faculty of Engineering, Osaka University, 工学部, 助教授 (30029251)
• Project Period (FY): 1985 – 1986
• Keywords: vertical vibration of ships / coupled vibration / ship hull / local structure / bottom structure / 付加水質量 / 二層梁 / 伝達マトリックス法

Research Abstract

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.