Session: SE-05-01 Structural Dynamics

Paper Number: 105288

105288 - Study on Vertical Load Acting on Whole Roof of Cylindrical Tanks in Nonlinear Sloshing Including Extremely Large Load 

When a cylindrical tank is excited by seismic waves, the motion of free liquid surface, called sloshing, may occur inside the tank. When the high-amplitude sloshing occurs, the free liquid surface collides with the roof of cylindrical tank, and the impulsive vertical load acts on the roof.
In the past study, authors proposed the predictive evaluation method of the vertical load acting on the roof of a cylindrical tank. This method consists of the impact pressure model with the direct evaluation model of liquid spreading velocity, the simplified evaluation model of nonlinear sloshing liquid surface and the local liquid surface wave model for the nonlinear liquid surface behavior induced by roof collision. It was showed that the predictive evaluation method almost agreed with test results of the maximum vertical load acting on the load measurement equipment, which was attached on a part of the roof of test model, under the condition of high roof height and low roof height from the still liquid surface. However, the predictive evaluation method had not been verified in the vertical load acting on the whole roof.
In this study, the vertical load acting on the whole roof was evaluated by the predictive evaluation method and CFD analysis performed under the condition of high roof height, low roof height and middle roof height from the still liquid surface. The predictive evaluation method almost agreed with the CFD analysis qualitatively, and its results tended to be larger than CFD analysis, in high roof height condition and low roof height condition. On the other hands, the CFD analysis result became extremely larger than the predictive evaluation method in middle roof height condition with a small excitation amplitude. Under the same condition, the CFD analysis result and the test result became extremely larger than the predictive evaluation method in the maximum load acting on the load measurement equipment. In this study, the cause of this extremely large load was discussed by analyzing the CFD analysis result. As a result, it was showed that the previous weak roof collision deformed the liquid surface into a flat shape and the flat liquid surface collided with the roof. The phenomenon caused the extremely large load acting on the roof. From this result, it was clarified that the history of roof collision has a large influence on the vertical load acting on the roof.

Presenting Author: Shunichi Ikesue Mitsubishi Heavy Industries, Ltd.

Presenting Author Biography: Academic Background
Graduated Kyoto Univ. in 1997 (Faculty of Engineering, Division of Civil Engineering)
Graduated Kyoto Univ. in 1999 (Master's Program, Graduate School of Engineering, Department of Civil Engineering)
Doctoral Degree (Dissertation), Kyoto Univ. in 2007

Career
(1999-2005) Steel Structure & Civil Engineering Laboratory, Hiroshima R&D Center, Mitsubishi Heavy Industries, Ltd.
(2005-2014) Fluid Dynamics Laboratory, Nagasaki R&D Center, Mitsubishi Heavy Industries, Ltd.
(2014-2015) Research Manager, Fluid Dynamics Laboratory, Nagasaki R&D Center, Mitsubishi Heavy Industries, Ltd.
(2015-2019) Research Manager, Fluid Dynamics No.1 Laboratory, Fluid Dynamics Research Department, Research & Innovation Center, Mitsubishi Heavy Industries, Ltd.
(2019-2022) Manager, Fluid Dynamics No.1 Laboratory, Fluid Dynamics Research Department, Research & Innovation Center, Mitsubishi Heavy Industries, Ltd.
(2022-present) Research Manager, Fluid Dynamics No.1 Laboratory, Fluid Dynamics Research Department, Research & Innovation Center, Mitsubishi Heavy Industries, Ltd.

Authors:

Shunichi Ikesue Mitsubishi Heavy Industries, Ltd.
Hideyuki Morita Mitsubishi Heavy Industries, Ltd.
Hiromi Sago Mitsubishi Heavy Industires, Ltd.
Shinobu Yokoi Mitsubishi FBR Systems, Inc.
Tomohiko Yamamoto Japan Atomic Energy Agency