Method of Designing the Composite Mooring Line.

Research Project

Project/Area Number	60460147
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	船舶構造・建造
Research Institution	KYUSHU UNIVERSITY
Principal Investigator	SUHARA T. Prof. Research Institute for Applied Mechanics, Kyushu Univ., 応用力学研究所, 教授 (60038528)
Co-Investigator(Kenkyū-buntansha)	OHKUSU M. Prof. Research Institute for Applied Mechanics, Kyushu Univ., 応用力学研究所, 教授 (70038537) TSUJI I. Prof. Faculty of Engineering, Kyushu Univ., 工学部, 教授 (80037697) HIYAMA H. Research Associate. Res. Inst. Appl. Mech., Kyushu Univ., 応用力学研究所, 助手 (30038541) YAMAKOSHI @m. Prof. Faculty of Engineering, Kyushu Univ., 工学部, 教授 (00037657) KOTERAYAMA W. Prof. Research Institute for Applied Mechanics, Kyushu Univ., 応用力学研究所, 教授 (80038562)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥7,400,000 (Direct Cost: ¥7,400,000) Fiscal Year 1986: ¥2,700,000 (Direct Cost: ¥2,700,000) Fiscal Year 1985: ¥4,700,000 (Direct Cost: ¥4,700,000)
Keywords	Mooring Line / Chain / Wire-Rope / Composite Mooirng Line System / Vibration / 変動張力
Research Abstract	This paper deals with the approximate method for calculating the dynamic tension of simple and the composite mooring lines which is anchored in slack condition on the sea bed and is forced to oscillate vertically and horizontally at its upper end. An extensive series of experiments has been conducted to clarify the mechanism of generating the dynamic tension and the snapping of a mooring line. Using the results of experiments, the cable's shape during oscillation is approximated as a catenary line. Moreover, the oscillation of each component of a mooring line is idealized as a single-degree-of-freedom motion of one lumped mass. The dynamical equation of the motion of the mass are solved over a broad range of forcing amplitude and periods of practical use, and their threshold values for the snap are obtained analytically. The calculated results are in good agreement with those of the experiments.