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  本文關鍵詞：集裝箱船用高強度厚鋼板的裂紋擴展分析及斷裂評定　出處：《上海交通大學》2014年碩士論文　論文類型：學位論文

  更多相關文章： 疲勞裂紋擴展 疲勞載荷 簡化方法 譜分析 設計波 高強度厚鋼板 失效評估圖 應力強度因子

【摘要】：疲勞是船舶結構破壞的主要模式之一。高強度鋼的應用使得結構的疲勞問題更加突出。大型集裝箱船上甲板由于存在大開口，通常采用高強度厚鋼板制造，，因此有必要對其焊接缺陷部位進行損傷容限和疲勞安全壽命的計算。本文主要做了以下工作： 1)介紹了疲勞載荷響應應力長期分布的模型和確定疲勞應力長期分布的簡化方法、譜分析法、設計波法。對DNV、CCS和JTP-CSR規(guī)范的簡化方法進行了比較并應用簡化方法對一艘40000T油船進行了應力范圍長期分布的計算，發(fā)現不同規(guī)范的簡化方法計算結果差異很大。 2)介紹了結構疲勞評估的累積損傷法和斷裂力學法。后者更能體現結構疲勞的本質，并能夠解釋一些疲勞現象。對于初始缺陷大量存在的焊接接頭，斷裂力學法更適用。 3)以直接計算法確定的兩參數Weibull分布為應力范圍的長期分布，疲勞載荷用計算機生成服從應力范圍長期分布的偽隨機數表示，采用單一裂紋擴展率曲線模型預報裂紋在任意時刻的尺寸，結合應力強度因子和參考應力的簡化計算方法和失效評估圖技術提出了一套適用于計算船用高強度厚鋼板損傷容限和疲勞安全壽命的方法。 4)通過編制計算程序對含初始裂紋的某集裝箱船甲板對接接頭焊縫進行了疲勞壽命評估。最后分析了疲勞載荷譜對安全壽命的影響，經計算表明載荷回復期的長短和Weibull分布的形狀參數的取值都會極大影響結構疲勞安全壽命。
[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 .

【學位授予單位】：上海交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U674.131;U661.4

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相關期刊論文 前3條

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