The study of storm loading simulation model for fatigue strength assessment of ship structural members

Tomita et al.提出了一种用于船体结构疲劳强度评估的风暴载荷仿真模型。他们分析了从大量船舶收集的遭遇波浪数据，并引入了随机加载模型。该模型与霍布根波浪频率表等计算波浪荷载长期分布的波浪频率表不一致，本研究的目的是引入一种新的风暴荷载模拟模型，该模型与波浪频率表一致。为了模拟船舶遭遇波况(有效波高、平均波周期和波向与航向的相对夹角)的时程，分析了日本和北美航道5年(1995-1999年)的后预报波况资料，并将实测值与欧洲中心WF后预报资料进行了比较。为此，验证了所遇到的波浪情况的时程。根据遇浪资料，远洋船舶遇浪情况可分为以下两类：风暴情况和平静情况。这两种情况是按随机顺序交替出现的，本文提出了一种与航道海浪频率表相一致的海浪模拟模型。这就是所谓的风暴负荷模型。我们论证了一种使用裂纹扩展低的VLCC结构的疲劳强度评估方法

Tomita et al. proposed a storm loading simulation model for a ship hull structural fatigue strength assessment. They analyzed encountered wave data collected from large number of ships and introduced the random loading model. The model is not consistency with a wave frequency table to calculate a long-term distribution of wave-induced load, such as Hobgen's wave frequency table.The purpose of this study is to introduce a new storm loading simulation model which is consistent in a wave frequency table. To simulate the time history of encountered wave condition by ship (significant wave height, mean wave period and relative angle between wave direction and ship course), we analyze a dataset of hindcast wave condition between Japan and North American shipping route over 5 years (1995-1999) and comparing measured buoy wave data and ECMWF hindcast data. To do so, the time histories of encountered wave condition are verified. Based on the encountered wave data, encountered wave conditions of ocean-going ships can be grouped into the following two classes : storm conditions and calm conditions. These two kinds of conditions appear alternatively in random order.We propose a wave simulation model which is consistent with a wave frequency table along with shipping route. This is called the storm loading model. We demonstrate a fatigue strength evaluation of VLCC structure employing a crack propagation low