集装箱船用高强度厚钢板的裂纹扩展分析及断裂评定

发布时间：2018-01-08 03:33

本文关键词：集装箱船用高强度厚钢板的裂纹扩展分析及断裂评定　出处：《上海交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：疲劳是船舶结构破坏的主要模式之一。高强度钢的应用使得结构的疲劳问题更加突出。大型集装箱船上甲板由于存在大开口，通常采用高强度厚钢板制造，，因此有必要对其焊接缺陷部位进行损伤容限和疲劳安全寿命的计算。本文主要做了以下工作： 1)介绍了疲劳载荷响应应力长期分布的模型和确定疲劳应力长期分布的简化方法、谱分析法、设计波法。对DNV、CCS和JTP-CSR规范的简化方法进行了比较并应用简化方法对一艘40000T油船进行了应力范围长期分布的计算，发现不同规范的简化方法计算结果差异很大。 2)介绍了结构疲劳评估的累积损伤法和断裂力学法。后者更能体现结构疲劳的本质，并能够解释一些疲劳现象。对于初始缺陷大量存在的焊接接头，断裂力学法更适用。 3)以直接计算法确定的两参数Weibull分布为应力范围的长期分布，疲劳载荷用计算机生成服从应力范围长期分布的伪随机数表示，采用单一裂纹扩展率曲线模型预报裂纹在任意时刻的尺寸，结合应力强度因子和参考应力的简化计算方法和失效评估图技术提出了一套适用于计算船用高强度厚钢板损伤容限和疲劳安全寿命的方法。 4)通过编制计算程序对含初始裂纹的某集装箱船甲板对接接头焊缝进行了疲劳寿命评估。最后分析了疲劳载荷谱对安全寿命的影响，经计算表明载荷回复期的长短和Weibull分布的形状参数的取值都会极大影响结构疲劳安全寿命。
[Abstract]:Fatigue is one of the main modes of ship structural damage . The application of high strength steel makes the structural fatigue problem more prominent . Because of the large opening in the upper deck of large container ship , it is usually made of high strength thick steel plate , so it is necessary to calculate the damage tolerance and fatigue safety life of its welded defects . 1 ) The model of long - term distribution of fatigue load response stress and the simplified method of determining the long - term distribution of fatigue stress are introduced , and the simplified method for determining the long - term distribution of fatigue stress is compared and the simplified method is applied to calculate the long - term distribution of the stress range of a 40000T tanker . 2 ) The cumulative damage method and fracture mechanics method of structural fatigue assessment are introduced . The latter can embody the essence of structural fatigue and can explain some fatigue phenomena . For the welded joints with large initial defects , the fracture mechanics method is more suitable . 3 ) The two - parameter Weibull distribution determined by the direct calculation method is the long - term distribution of the stress range , and the fatigue loading computer generates a pseudo - random number subject to the long - term distribution of the stress range , and a set of methods suitable for calculating the damage tolerance and fatigue safety life of the ship high - strength thick steel plate is put forward by using a single crack growth rate curve model to predict the dimension of the crack at any moment , the simplified calculation method of combining the stress intensity factor and the reference stress and the failure evaluation map technology . 4 ) The fatigue life of the welded joint of the deck of a container ship with the initial crack is evaluated by the calculation program . Finally , the influence of the fatigue load spectrum on the safety life is analyzed , and the calculation shows that the value of the shape parameter of the length of the load recovery period and the Weibull distribution can greatly influence the fatigue life of the structure .

【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U674.131;U661.4

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