2022 Fiscal Year Final Research Report

Practical application of combined vibration damping device corresponding to different vibration phenomena of sloshing and bulging of water tank

Research Project

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Project/Area Number	20K04667
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 22020:Structure engineering and earthquake engineering-related
Research Institution	Chuo University
Principal Investigator	HIROKAZU HIRANO 中央大学, 総合政策学部, 教授 (80256023)
Co-Investigator(Kenkyū-buntansha)	佐藤尚次中央大学, 理工学部, 教授 (30162457) 鈴木森晶愛知工業大学, 工学部, 教授 (90273276)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	バルジング / スロッシング / 振動実験 / 構造と流体の連成解析 / 制振装置 / 貯水槽
Outline of Final Research Achievements	In this study, we developed a composite damping system that can cope with two different types of vibration phenomena, sloshing and bulging, that occur in water tanks during earthquakes, and that can improve the seismic resistance of existing water tanks. In particular, we investigated the bulging vibration characteristics of non-earthquake resistant FRP water tanks that were manufactured before the seismic design standard for tanks was established in 1980 and developed damping device against bulging vibration. We carried out vibration experiment using a non-earthquake resistant tank. The damping device was attached to corner of the tank, because bulging vibration cause damage particularly to there. As a result, it was found that by damping device, deformation of the tank’s panel was decreased. In addition, we confirmed damping effect, reducing repeated occurrence of large displacements and large accelerations to the tank by performing rainflow analysis.
Free Research Field	地震工学
Academic Significance and Societal Importance of the Research Achievements	本研究で壁面の剛性とタンク全体で剛性のバランスが重要であることを掴んだ。特にステンレス製パネルタンクは、内部の補強材と壁面パネルの接続部で極端な剛性差があることから、隅角部が弱点となりここがバルジングによる破損発生箇所となる。さらに、静的な荷重を割り増しての耐震設計であることから繰り返し荷重の検討がなされていないので、設計上は引っ張り荷重のみの補強部材に圧縮力が生じ座屈を起こすことも判った。FRPタンクも同様な傾向にあるが、外補強の効果がある。バルジング対策案の制振装置の検討は、隅角部が弱点になることから、ここに制振装置を設置することで該当する貯水槽の耐震化向上に効果があるものと考えられる。