報告書番号

U97056

タイトル（和文）

ＦＢＲ垂直隔壁の地震時流体連成座屈評価（その２） -多重円筒殻の流体連成動的座屈評価法の開発と適用性検証-

タイトル（英文）

Evaluation of Fluid-coupled Seismic Buckling Strength for FBRs' thermal liners (2)- Development of a Simplified Method for Evaluating Fluid-coupled Buckling Strength of Co-axial Cylinders and Applicab

概要 （図表や脚注は「報告書全文」に掲載しております）

FBR垂直隔壁は，多重円筒構造物であり，地震時の流体連成座屈の発生を防止するために，隔壁の座屈挙動を解明し，適切な座屈評価法を確立することが設計上必要となる．前報では，開発した解析プログラムAXISにより，液体を満たした薄肉円筒模型の動的座屈試験を対象に、非線形時刻歴解析を実施し、同プログラムの妥当性を検証したが，実際の隔壁のような多重円筒に関する検討は未着手であった．本報の目的は，隔壁の座屈挙動を振動台試験やAXISによる非線形解析により把握し、簡便な評価法を提案するとともに、その適用性を明らかにすることである．このため，液体を満たした二重円筒模型を用いた振動台試験及びAXISによる非線形時刻歴応答解析を実施し，流体圧による外圧座屈が隔壁に発生することを確認した．さらに，試験や非線形解析から得られた座屈強度と提案法による評価値とを比較し、実際の座屈強度を安全側に評価することを確認した．

概要 （英文）

The demonstration FBRs' thermal liners are multi-walled coaxial cylindrical shells. In the seismic design of the shells, it is very important to prevent the dynamic buckling due to seismically induced hydrodynamic effects. Therefore, it is necessary to clarify the fluid-coupled dynamic buckling behaviour of the shells and to establish a simplifed method for evaluating the buckling strength. For this particular problem in FBRs, authors have already indicated that dynamic buckling analyses of a liquid-filled thin cylindrical tank subjected to harmonic excitations may be possible by using the computer program AXIS within reasonable computational time and the computer program could simulate the test results well. However, the seismic buckling phenomena of fluid-coupled multi-walled coaxial cylindrical shells, such as the thermal liners, have not been investigated yet. The objectives of this study are to propose a simplifed method for evaluating the buckling strength of the shell structures, and to validate the applicability of the proposed method, based on shaking table test data and numerical simulations by using AXIS. Shaking table tests were conducted in order to investigate the fluid-coupled buckling strength of two coaxial cylindrical shells, and non-linear earthquake response analyses by using AXIS were also performed. Based on those results, the buckling of the thermal liners due to external hydrodynamic pressure was clarified. Futhermore, the applicability of the proposed method was shown through comparing with the results of the shaking table tests and numerical simulations.

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