Development of an aperiodic and no power required vertical seismic isolation system using a hydraulic cylinder

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04676
• 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: National Research Institute for Earth Science and Disaster Prevention
• Principal Investigator: Yamada Manabu 国立研究開発法人防災科学技術研究所, 地震減災実験研究部門, 主幹研究員 (10835763)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 鉛直免震 / パラレルリンク / 固有周期 / 力学特性 / 復元力特性 / 摩擦力 / 無動力

Outline of Final Research Achievements

Parallel link vertical base isolation was studied by analysis and small mock-up. The results of the analysis showed that the use of a supported parallel link in the passive method causes unstable behavior where the displacement of the cylinder expands. Therefore, we changed to a suspension type parallel link that can solve this problem. In the suspension type, where the cylinder is used in the retracted direction, the force vector and the force point of the cylinder connection are aligned, so smooth motion can be expected. It also works to reduce frictional force, which is the biggest weak point of the cylinder system. Four pneumatic type and one hydraulic type were fabricated as small mockups and subjected to vibration tests, which showed good results in reducing the input acceleration. The current design specifications for 250 t/leg are summarized.

Free Research Field

機械工学

Academic Significance and Societal Importance of the Research Achievements

南海トラフ地震が確実視され，その備えが必要である。そこで，フライトシミュレータ等に用いられるパラレルリンクを鉛直免震装置に適用する検討を実施した。パラレルリンクは，関節を順次連結するシリアルリンクと比較して，堅強な構造を作る事ができるが，地震力を受け流す方向で使う場合，水平復元力が乏しく，不安定挙動を示すことが本研究で明らかになった。そこで，支持型から懸架型に変更することで復元性を向上し，安定化できる見通しを得た。小型モックアップの加振実験では一定の免震性能を確認している。今後，ほとんど実用化されていない鉛直免震の有望な方式として発展が期待される。