Hybrid Fatigue Life Assessment considering Meso- and Macro-scale Cyclic Plasticity Analysis
| Project/Area Number |
17H03489
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Naval and maritime engineering
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥16,250,000 (Direct Cost: ¥12,500,000、Indirect Cost: ¥3,750,000)
Fiscal Year 2019: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2018: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2017: ¥9,100,000 (Direct Cost: ¥7,000,000、Indirect Cost: ¥2,100,000)
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| Keywords | 疲労 / 塑性 / 破壊 / 溶接 / 数値解析 / 損傷 / 亀裂発生 / 亀裂伝播 / 塑性変形 / 弾塑性 / 繰返し塑性 / 結晶塑性 / ハイブリッド / 鋼構造 / き裂 / 熱影響 / 結晶 / マクロ / メゾ / HAZ / 寿命 / 構造体 |
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| Outline of Final Research Achievements |
It is considered that fatigue life can be divided into two separate contributions: the crack initiation life and crack propagation life. The purpose of this research is to propose a methodology for predicting fatigue crack initiation and propagation life of weld joint using an unconventional elasto-plasticity model called the FSS model. The FSS model is based on the Subloading Surface theory, which was enriched by including the elastic boundary and cyclic damage concepts for the description of strain softening behavior within macroscopically elastic stress state. The model was used to investigate the inelastic response of the material under different cyclic loading conditions. In this study, finite element analysis was conducted to assess the fatigue crack initiation life and subsequently propagation life by extending the assessment method for fatigue crack initiation life by considering a cyclic plasticity accumulation during fatigue loading.
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| Academic Significance and Societal Importance of the Research Achievements |
疲労に起因する損傷事例は数多く報告されており，そのうちの多くが溶接継手部に確認されている。そのため、これまでに鋼材および溶接継手の疲労寿命評価について数多くの有用な知見が示されている。しかし、溶接構造物の疲労に関する実験的検討では，一般にき裂の起点となる溶接止端部等の応力集中部は形状が複雑であり、溶接プロセスに伴い発生する残留応力も重畳することから各種影響因子を定量的に評価することは容易ではない。そこで本研究では、疲労損傷のメカニズムを反映した寿命評価手法を開発するものである。
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Report
(4 results)
Research Products
(136 results)
