Spectral Fatigue Analysis with Hydro-elastic effect of Bulk carrier
Date Issued
2012
Date
2012
Author(s)
Tsai, Ssu-Chieh
Abstract
The purpose of this paper is to explore when the ship forced not only by hydrodynamic but also by hydro-elastic with spectral fatigue analysis method, the influence of fatigue damage as well as fatigue life on the stress concentration area which occurred easily.
In the sailing life, ship will bear not only static pressures from water, weight of cargo and light ship, but dynamic load such as cycle-loading under irregular dynamic wave. These dynamic loads will make ship structure occur fatigue damage, and the extra cumulative fatigue damage caused by ship springing phenomenon can’t be ignored. Recent years, the trend of lightweight design and increased usage of high tensile steel made the hull girder natural frequency significantly reduced, lower enough to vibrate with the wave environment, and getting into the ship and wave encounter frequency. It’s common to hear shipwrecks due to fatigue damage, as a result, the fatigue strength of ship structure become one of the analyzing point in the process of ship design.
In this study, it will use the theory of hydro-elastic (HE) and developed analysis software to calculate the hydro-elastic effect from interaction between ships and wave with mode superposition method. In the analysis process, we develop the theoretical and fundamental research result for hydrodynamics and hydro-elastic calculations. According to the SFA guidance provided by the Bureau Veritas classification society (BV), using 203,000 DWT bulk carrier as the reference ship and to carry out the fatigue damage assessment, finding out the improved-design ways under spectral fatigue analysis.
In the sailing life, ship will bear not only static pressures from water, weight of cargo and light ship, but dynamic load such as cycle-loading under irregular dynamic wave. These dynamic loads will make ship structure occur fatigue damage, and the extra cumulative fatigue damage caused by ship springing phenomenon can’t be ignored. Recent years, the trend of lightweight design and increased usage of high tensile steel made the hull girder natural frequency significantly reduced, lower enough to vibrate with the wave environment, and getting into the ship and wave encounter frequency. It’s common to hear shipwrecks due to fatigue damage, as a result, the fatigue strength of ship structure become one of the analyzing point in the process of ship design.
In this study, it will use the theory of hydro-elastic (HE) and developed analysis software to calculate the hydro-elastic effect from interaction between ships and wave with mode superposition method. In the analysis process, we develop the theoretical and fundamental research result for hydrodynamics and hydro-elastic calculations. According to the SFA guidance provided by the Bureau Veritas classification society (BV), using 203,000 DWT bulk carrier as the reference ship and to carry out the fatigue damage assessment, finding out the improved-design ways under spectral fatigue analysis.
Subjects
Hydro-elastic
Shot term distribution
Long term distribution
Cumulative damage rule
Fatigue life
Type
thesis
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