A Study on Fatigue Strength of Large Container Ship with Taking the Effect of Hull Girder Vibration into Account

摘要

With regard to the fatigue strength, the effects of the cyclic stress due to hull girder vibration have not been clarified. Particularly, there are few reports of hull fracture due to such vibration although serious damage may be predicted in the computation. It is considered that there are many uncertainties of factors for the precise prediction of fatigue strength. Based on this back ground, authors perform the analysis of fatigue strength utilizing both data by means of tank test using backbone type elastic model and actual stress by full scale measurement. The effect of operational factor on the fatigue damage is quantitatively clarified. Although the long-term fatigue damage is very low, it is clarified that hull girder vibration due to whipping has much effect on fatigue damage. Therefore, it is important to estimate accurately the level and probability of occurrence of whipping stress.