| 研究課題/領域番号 |
21J12176
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| 研究機関 | 九州大学 |
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研究代表者 |
TUBEI Valary 九州大学, 工学府, 特別研究員(DC2)
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| 研究期間 (年度) |
2021-04-28 – 2023-03-31
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| キーワード | Fatigue / Short crack / Crack closure / 3D/4D observation / X-ray tomography |
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| 研究実績の概要 |
This study’s goal is to develop a crystal plasticity FEM (CPFEM) model that simulates short fatigue crack closure behavior based on real 3D crack morphology. The aim to understand closure mechanisms and how microstructure can be manipulated such that closure is enhanced hence realizing materials that are difficult to fracture.
So far, we have analyzed 3D crack growth and closure behavior and evolution with time (4D) using X-ray tomography. Crack growth was observed to vary with crack extension caused by evolution of crack morphology and its interaction with Ti-6Al-4V alloy phases (α and α+β) with distinct inherent crack growth resistance. It was found that inclined and overlapped crack segments which occurred mainly in α+β showed early crack closure and subsequently low crack growth rate. These results indicate that certain microstructure may promote the formation of a complex crack morphology which contribute to fracture resistance. Further analysis will be done using CPFEM simulations.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The main objectives of this study are:
1.To assess crack closure behavior in 3D using X-ray tomography: So far, data for assessing the relationship between local 3D crack growth and closure behavior has been acquired successfully. The data analysis has been completed and the results are currently being prepared for publication.
2.To develop an image based CPFEM model that simulates short crack closure in relation to the underlying microstructure. The aim is to understand how to control the closure mechanisms ultimately realizing materials that are difficult to fracture: Currently the crack and microstructure model is being prepared to carry out the simulations. It is expected that the simulation will be completed within the 2022 fiscal year.
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| 今後の研究の推進方策 |
To promote this study, first a complete analysis of crack closure mechanisms in relation with the underlying microstructure will be done using the CPFEM model that is currently being prepared. From this, understand how microstructure can be manipulated i.e., during processing such that crack closure is enhanced to realize materials that are difficult to fracture. Secondly, the results of this study will be presented in conferences (both domestic and international) and published in an international journal.
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