深海半潛平臺剩余疲勞.doc
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深海半潛平臺剩余疲勞,摘要深海半潛平臺作為深海海洋油氣開采的主流設備，體積龐大，結構復雜，造價成本高，工作環(huán)境極其惡劣。海洋平臺一旦發(fā)生安全性事故，不僅會帶來巨大的經(jīng)濟損失、人員傷亡，而且還會嚴重的污染環(huán)境。所以對深海半潛平臺進行剩余疲勞壽命預報是極其重要的。本文基于abs《近海結構物疲勞評估規(guī)范》，以某深水半潛式海洋平臺為目標，首先根據(jù)平...
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此文檔由會員 違規(guī)屏蔽12 發(fā)布
摘 要
深海半潛平臺作為深海海洋油氣開采的主流設備，體積龐大，結構復雜，造價成本高，工作環(huán)境極其惡劣。海洋平臺一旦發(fā)生安全性事故，不僅會帶來巨大的經(jīng)濟損失、人員傷亡，而且還會嚴重的污染環(huán)境。所以對深海半潛平臺進行剩余疲勞壽命預報是極其重要的。
本文基于ABS《近海結構物疲勞評估規(guī)范》，以某深水半潛式海洋平臺為目標，首先根據(jù)平臺整體結構強度的計算結果，選取高應力區(qū)為關鍵節(jié)點部位，建立關鍵節(jié)點的精細有限元模型，進行結構強度分析，進而找到結構的疲勞熱點。然后分別利用S-N曲線累積損傷方法和斷裂力學方法對半潛平臺關鍵節(jié)點進行剩余疲勞壽命分析，并將不同役齡半潛平臺的腐蝕損傷和裂紋損傷考慮到有限元模型中，計算不同服役年限下受腐蝕和裂紋損傷后的疲勞熱點應力，最后得到不同服役年限（每5年為周期）下平臺關鍵節(jié)點的剩余疲勞壽命。
通過本文研究得出的主要結論如下：
（1）基于S-N曲線方法和斷裂力學方法對不同服役年限（按每5年為周期）關鍵節(jié)點一的剩余疲勞壽命進行分析，并考慮腐蝕損傷和裂紋損傷，得到了隨平臺服役年限的增加，平臺的剩余壽命不斷降低的結論；同時計算結果顯示該平臺滿足ABS規(guī)范設計使用壽命要求。
（2）考慮腐蝕損傷和裂紋損傷的疲勞壽命比不考慮這些因素分析的疲勞壽命要短，這符合深海半潛平臺的實際工作環(huán)境，疲勞壽命結果更偏合理和安全。
（3）海洋結構物是焊接結構，不可避免的會產(chǎn)生裂紋，隨著服役年限的增加，裂紋有不斷擴展的趨勢，從而影響平臺的使用壽命。通過S-N曲線方法和斷裂力學方法對半潛平臺疲勞壽命的研究比較發(fā)現(xiàn)，利用基于裂紋擴展原理的斷裂力學方法對半潛平臺預報的剩余疲勞壽命要短，更具有合理性。
（4）通過分析發(fā)現(xiàn)立柱與橫撐連接處，承受較大的交變載荷，疲勞壽命比立柱與上甲板連接處小，但滿足ABS規(guī)范設計的使用壽命要求，是影響平臺疲勞壽命的關鍵點。而且此部位長期受到海水的腐蝕作用，應加強日常檢修和維護。特別要加大老齡半潛平臺特別是進入后期服役平臺的檢修與維護頻度，防止意外事故的突然發(fā)生。
關鍵詞：深海半潛式平臺 疲勞壽命預報 S-N曲線 斷裂力學
Abstract
Deepwater semi-submersible platform with complicated large structure and high cost is widely used in deep sea energy exploration and often works in extremely bad environment. Security incidents of offshore platforms will not only bring great economic loss, casualties but also bring serious pollution of environment. So fatigue life of deepwater semi-submersible platform is necessary and significant to be studied.
In this paper, the fatigue life of a deepwater semi-submersible is studied based on ABS Offshore Structures Fatigue Assessment Rules. Firstly, according to the global strength analysis, the high sress areas of the node positions are selected as key joints.The finite element models of the key joints are established. The strength analysis of the key joints is calculated and fatigue hot spots are found. Then the fatigue life of the key joints is studied based on S-N curves and fracture mechanics, which both considering corrosion damage and crack damage every 5 years. The main research conclusions of this paper are listed below:
(1) The remaining fatigue life of the platform is calaulated based on S-N curve method and fracture mechanics method every 5 years. The corrosion damage and crack damage is considered. The conclusion is that the remaining fatigue life is reduced with the service time increasing. So high-frequency repair and maintenance is needed for the aging platform to prevent sudden accidents.
(2) The remaing fatigue life becomes shorter when considering corrosion damage and crack damage, which agrees with the actural working environment.
(3) Semi-submersible platform is welded structure and cracks are inevitable.The remaing fatigue life is reduced because of crack propagation with the service time increasing. The fracture mechanics method is more reasonable to forecaste the fatigue life of the platform.
(4) The connection of the column and the brace of the semi-submersible platform is the important joint. It suffers from higher cyclic load and it has lower fatigue life than the connection of the column and the upper deck. It determines platform service life. So the routine repair and maintenance is espically needed for the aging platform.
Key words: deepwater semi-submersible platform; fatigue life analysis; S-N curve; fracture mechanics
目 錄
摘 要 I
Abstract III
目 錄 I
Contents I
第一章 緒 論 1
1.1 研究背景及意義 1
1.2 國內外研究方法和現(xiàn)狀 3
1.2.1 S-N曲線方法研究現(xiàn)狀 3
1.2.2 斷裂力學方法研究現(xiàn)狀 4
1.2.3 可靠性方法研究現(xiàn)狀 5
1.2.4 三種疲勞方法比較研究總結 6
1.3 本文主要研究工作和創(chuàng)新點 6
1.3.1 主要工作 6
1.3.2 創(chuàng)新點 7
第二章 海洋結構物疲勞壽命預報方法 8
2.1 S-N曲線法 8
2.1.1 簡化分析法 8
2.1.2 確定性法 9
2.1.3 譜分析法 9
2.2 斷裂力學法 9
2.3 疲勞可靠性分析 11
2.4 本章小結 12
第三章 基于ABS規(guī)范的近海結構物疲勞壽命預報方法 13
3.1 引言 13
3.1.1 疲勞評定的基本方法 13
3.1.2 累積損傷規(guī)律和疲勞安全檢測 14
3.1.3 現(xiàn)存結構 15
3.1.4 總結 15
3.2 基于S-N曲線的疲勞強度 16
3.2.1 概述 16
3.2.2 名義應力法 17
3.2.3..
深海半潛平臺作為深海海洋油氣開采的主流設備，體積龐大，結構復雜，造價成本高，工作環(huán)境極其惡劣。海洋平臺一旦發(fā)生安全性事故，不僅會帶來巨大的經(jīng)濟損失、人員傷亡，而且還會嚴重的污染環(huán)境。所以對深海半潛平臺進行剩余疲勞壽命預報是極其重要的。
本文基于ABS《近海結構物疲勞評估規(guī)范》，以某深水半潛式海洋平臺為目標，首先根據(jù)平臺整體結構強度的計算結果，選取高應力區(qū)為關鍵節(jié)點部位，建立關鍵節(jié)點的精細有限元模型，進行結構強度分析，進而找到結構的疲勞熱點。然后分別利用S-N曲線累積損傷方法和斷裂力學方法對半潛平臺關鍵節(jié)點進行剩余疲勞壽命分析，并將不同役齡半潛平臺的腐蝕損傷和裂紋損傷考慮到有限元模型中，計算不同服役年限下受腐蝕和裂紋損傷后的疲勞熱點應力，最后得到不同服役年限（每5年為周期）下平臺關鍵節(jié)點的剩余疲勞壽命。
通過本文研究得出的主要結論如下：
（1）基于S-N曲線方法和斷裂力學方法對不同服役年限（按每5年為周期）關鍵節(jié)點一的剩余疲勞壽命進行分析，并考慮腐蝕損傷和裂紋損傷，得到了隨平臺服役年限的增加，平臺的剩余壽命不斷降低的結論；同時計算結果顯示該平臺滿足ABS規(guī)范設計使用壽命要求。
（2）考慮腐蝕損傷和裂紋損傷的疲勞壽命比不考慮這些因素分析的疲勞壽命要短，這符合深海半潛平臺的實際工作環(huán)境，疲勞壽命結果更偏合理和安全。
（3）海洋結構物是焊接結構，不可避免的會產(chǎn)生裂紋，隨著服役年限的增加，裂紋有不斷擴展的趨勢，從而影響平臺的使用壽命。通過S-N曲線方法和斷裂力學方法對半潛平臺疲勞壽命的研究比較發(fā)現(xiàn)，利用基于裂紋擴展原理的斷裂力學方法對半潛平臺預報的剩余疲勞壽命要短，更具有合理性。
（4）通過分析發(fā)現(xiàn)立柱與橫撐連接處，承受較大的交變載荷，疲勞壽命比立柱與上甲板連接處小，但滿足ABS規(guī)范設計的使用壽命要求，是影響平臺疲勞壽命的關鍵點。而且此部位長期受到海水的腐蝕作用，應加強日常檢修和維護。特別要加大老齡半潛平臺特別是進入后期服役平臺的檢修與維護頻度，防止意外事故的突然發(fā)生。
關鍵詞：深海半潛式平臺 疲勞壽命預報 S-N曲線 斷裂力學
Abstract
Deepwater semi-submersible platform with complicated large structure and high cost is widely used in deep sea energy exploration and often works in extremely bad environment. Security incidents of offshore platforms will not only bring great economic loss, casualties but also bring serious pollution of environment. So fatigue life of deepwater semi-submersible platform is necessary and significant to be studied.
In this paper, the fatigue life of a deepwater semi-submersible is studied based on ABS Offshore Structures Fatigue Assessment Rules. Firstly, according to the global strength analysis, the high sress areas of the node positions are selected as key joints.The finite element models of the key joints are established. The strength analysis of the key joints is calculated and fatigue hot spots are found. Then the fatigue life of the key joints is studied based on S-N curves and fracture mechanics, which both considering corrosion damage and crack damage every 5 years. The main research conclusions of this paper are listed below:
(1) The remaining fatigue life of the platform is calaulated based on S-N curve method and fracture mechanics method every 5 years. The corrosion damage and crack damage is considered. The conclusion is that the remaining fatigue life is reduced with the service time increasing. So high-frequency repair and maintenance is needed for the aging platform to prevent sudden accidents.
(2) The remaing fatigue life becomes shorter when considering corrosion damage and crack damage, which agrees with the actural working environment.
(3) Semi-submersible platform is welded structure and cracks are inevitable.The remaing fatigue life is reduced because of crack propagation with the service time increasing. The fracture mechanics method is more reasonable to forecaste the fatigue life of the platform.
(4) The connection of the column and the brace of the semi-submersible platform is the important joint. It suffers from higher cyclic load and it has lower fatigue life than the connection of the column and the upper deck. It determines platform service life. So the routine repair and maintenance is espically needed for the aging platform.
Key words: deepwater semi-submersible platform; fatigue life analysis; S-N curve; fracture mechanics
目 錄
摘 要 I
Abstract III
目 錄 I
Contents I
第一章 緒 論 1
1.1 研究背景及意義 1
1.2 國內外研究方法和現(xiàn)狀 3
1.2.1 S-N曲線方法研究現(xiàn)狀 3
1.2.2 斷裂力學方法研究現(xiàn)狀 4
1.2.3 可靠性方法研究現(xiàn)狀 5
1.2.4 三種疲勞方法比較研究總結 6
1.3 本文主要研究工作和創(chuàng)新點 6
1.3.1 主要工作 6
1.3.2 創(chuàng)新點 7
第二章 海洋結構物疲勞壽命預報方法 8
2.1 S-N曲線法 8
2.1.1 簡化分析法 8
2.1.2 確定性法 9
2.1.3 譜分析法 9
2.2 斷裂力學法 9
2.3 疲勞可靠性分析 11
2.4 本章小結 12
第三章 基于ABS規(guī)范的近海結構物疲勞壽命預報方法 13
3.1 引言 13
3.1.1 疲勞評定的基本方法 13
3.1.2 累積損傷規(guī)律和疲勞安全檢測 14
3.1.3 現(xiàn)存結構 15
3.1.4 總結 15
3.2 基于S-N曲線的疲勞強度 16
3.2.1 概述 16
3.2.2 名義應力法 17
3.2.3..
