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Improvement of Fatigue Strength by Laser Irradiation in the Hull Construction

Research Project

Project/Area Number 16K06918
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Naval and maritime engineering
Research InstitutionNational Institute of Maritime, Port and Aviation Technology

Principal Investigator

ANAI yosuke  国立研究開発法人海上・港湾・航空技術研究所, その他部局等, 研究員 (60470051)

Co-Investigator(Kenkyū-buntansha) 丹羽 敏男  国立研究開発法人海上・港湾・航空技術研究所, その他部局等, 研究員 (10208267)
岩田 知明  国立研究開発法人海上・港湾・航空技術研究所, その他部局等, 研究員 (50358397)
津村 秀一  国立研究開発法人海上・港湾・航空技術研究所, その他部局等, 研究員 (10782526)
Research Collaborator GOTOH koji  
Project Period (FY) 2016-04-01 – 2019-03-31
Project Status Completed (Fiscal Year 2018)
Budget Amount *help
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Keywords疲労強度 / レーザ照射 / 表質改善 / 疲労 / 疲労強度改善 / 表面改質
Outline of Final Research Achievements

In this study, we developed an efficient fatigue strength improvement method in hull construction by laser irradiation.
Laser irradiation was applied to the weld toe of fillet weld joints under multiple conditions, and the effects on factors affecting fatigue strength were examined. As a result, the weld toe radius increased and stress concentration at weld toe was relaxed. On the other hand, in regard to grain refining and residual stress, no significant improvement effect to affect the fatigue strength was found in the range of irradiation conditions in this study. Next, fillet weld joints irradiated with laser provided for fatigue tests. As a result, fatigue strength was improved by laser irradiation. It is considered that this is mainly due to the increase of the toe radius by the laser irradiation to the weld toe.

Academic Significance and Societal Importance of the Research Achievements

船舶は重要な社会資本として活用されているが、現在も多数の疲労損傷が報告されている。本研究の結果、船体の溶接工程においてレーザ照射を実施することにより効率的に船舶の疲労強度を改善可能なことが明らかとなった。これにより、疲労強度の観点から安全な船舶の建造が可能となり、安全かつ経済的な社会資本の構築に寄与するものと考えられる。
さらに、本研究の波及効果として、船体建造工程におけるレーザの活用が進むことにより、より変形の少ない高品質な船舶の建造、新たな船体構造様式の開発につながると期待される。

Report

(4 results)
  • 2018 Annual Research Report   Final Research Report ( PDF )
  • 2017 Research-status Report
  • 2016 Research-status Report

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Published: 2016-04-21   Modified: 2020-03-30  

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