Research of Springing and Whipping Influence on Ultra-Large Containerships' Fatigue Analysis

doi:10.1007/s12204-018-1956-3

Abstract

Abstract: Rules of Classiˉcation Societies all around the world have made changes on design wave loads' value and fatigue in°uence factor modiˉcation due to the in°uence of springing and whipping on ultra-large containerships. The paper ˉrstly introduced 3-D linear hydroelastic theory in frequency domain and 3-D nonlinear hydroelastic theory in time domain, considering large amplitude motion nonlinearity and slamming force due to the severe relative motion between ship hull and wave. Then the spectrum analysis method and time domain statistical analysis method were introduced, which can make fatigue analysis under a series of standard steps in frequency and time domain, respectively. Finally, discussions on the in°uence factor of springing and whipping on fatigue damages of 8500TEU and 10000TEU containerships with di?erent loading states were made. The fatigue assessment of di?erent position on the midship section was done on the basis of nominal stress. The fatigue damage due to whipping can be the same as the fatigue damage due to springing and even sometimes can be larger than the springing damage. Besides, some suggestions on calculating load case selection were made to minimize the quantity of work in frequency and time domain. Thus, tools for fatigue in°uence factor modiˉcation were provided to meet the demand of IACS-UR.

Key words: springing| whipping| fatigue analysis| hydroelasticity

摘要： Rules of Classiˉcation Societies all around the world have made changes on design wave loads' value and fatigue in°uence factor modiˉcation due to the in°uence of springing and whipping on ultra-large containerships. The paper ˉrstly introduced 3-D linear hydroelastic theory in frequency domain and 3-D nonlinear hydroelastic theory in time domain, considering large amplitude motion nonlinearity and slamming force due to the severe relative motion between ship hull and wave. Then the spectrum analysis method and time domain statistical analysis method were introduced, which can make fatigue analysis under a series of standard steps in frequency and time domain, respectively. Finally, discussions on the in°uence factor of springing and whipping on fatigue damages of 8500TEU and 10000TEU containerships with di?erent loading states were made. The fatigue assessment of di?erent position on the midship section was done on the basis of nominal stress. The fatigue damage due to whipping can be the same as the fatigue damage due to springing and even sometimes can be larger than the springing damage. Besides, some suggestions on calculating load case selection were made to minimize the quantity of work in frequency and time domain. Thus, tools for fatigue in°uence factor modiˉcation were provided to meet the demand of IACS-UR.

关键词: springing| whipping| fatigue analysis| hydroelasticity

CLC Number:

U 661

REN Huilong (任慧龙), ZHANG Kaihong (张楷弘), LI Hui (李辉). Research of Springing and Whipping Influence on Ultra-Large Containerships' Fatigue Analysis[J]. Journal of Shanghai Jiao Tong University (Science), 2018, 23(3): 429-.

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