| Project/Area Number |
21H01206
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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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| Review Section |
Basic Section 18010:Mechanics of materials and materials-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2023: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2022: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
Fiscal Year 2021: ¥9,750,000 (Direct Cost: ¥7,500,000、Indirect Cost: ¥2,250,000)
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| Keywords | 液滴 / 流動 / 凝固 / 皮膜 / 変形 / 破壊 / 残留応力 / 溶射 / 材料力学 / 密着 / コーティング |
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| Outline of Research at the Start |
本研究では，溶射プロセスをモデル化した溶融パラフィンの滴下実験により，基材に衝突した液滴の流動・凝固・密着過程での残留応力の発達挙動を可視化するとともに，凝固した皮膜の割れや剥離といった破壊現象に滴下条件が与える影響を解明する．滴下実験の結果に基づき，液滴の流動・凝固挙動を粒子法により再現するとともに，凝固皮膜の変形・破壊のメカニクスを熱構造連成有限要素解析により定量化し，高強度な皮膜の実現を果たす最適滴下条件の提案に繋げる．
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| Outline of Final Research Achievements |
A new experimental set-up was developed to examine residual stress evolution during the flow, solidification and adhesion processes of paraffin droplet impacting a solid substrate. The droplet material, droplet temperature, droplet impact velocity, and substrate preheating temperature were considered as experimental variables, and the effects of each were extracted separately by model experiments. The flow and solidification of the droplets were reproduced by fluid simulation, and the deformation and fracture mechanisms during the solidification and adhesion processes were quantified by coupled thermo-structural finite element analysis.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，溶射プロセスをモデル化した溶融パラフィンの滴下実験により，さまざまな滴下条件が残留応力の発達過程に及ぼす影響を個別に抽出した．また，数値解析を援用して，それぞれの滴下条件が液滴の流動・凝固過程と皮膜の変形・破壊機構に与える影響を可視化しながら，優れた皮膜強度を生み出す最適滴下条件を模索した．本研究で考察した凝固皮膜の強度問題は，液滴の衝突と流動を扱う流体力学，凝固と熱移動を扱う熱力学，変形と破壊を扱う材料力学が絡んだ複雑な問題だったが，現象を可視化しやすいパラフィンの滴下実験と数値解析により，この熱/流体/構造連成メカニクスの体系的な理解が得られた．
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