A fundamental study on fatigue life evaluation taking the load sequence of whipping into account.

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560995
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Naval and maritime engineering
• Research Institution: National Maritime Research Institute
• Principal Investigator: MASAYOSHI Oka 独立行政法人海上技術安全研究所, その他部局等, 研究員 (70450674)
• Co-Investigator(Kenkyū-buntansha): NIWA Toshio 国立研究開発法人海上技術安全研究所, 構造基盤技術系 保守管理技術研究グループ, グループ長 (10208267) ; TAKAMI Tomoki 国立研究開発法人海上技術安全研究所, 構造安全評価系 構造解析研究グループ, 研究員 (50586683)
• Research Collaborator: TAKAGI Ken 東京大学, 大学院新領域創成科学研究科海洋技術環境学専攻, 教授
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 疲労き裂伝播解析 / 嵐モデル / ホイッピング / マイナー則 / 大型コンテナ船 / ランダム波形 / 応力履歴 / 構造信頼性解析

Outline of Final Research Achievements

The fatigue crack length at 25 years old was simulated using the fatigue crack propagation analysis inputted a long-term stress history of a large container ship based on the storm model and stress RAO(Response Amplitude Operator). In order to simulate the delay phenomenon of fatigue crack growth, the fatigue crack propagation analysis program based on cohesive force model focuses on the plastic behavior of the crack tip, and it was extended to be able to treat any random waveform. The effect of whipping on fatigue life becomes clear in terms of crack length, the safety level of the Minor's law which generally adopted as current fatigue design was clarified .

Free Research Field

船体構造強度、波浪荷重、構造解析、疲労強度、船体振動