Wind borne debris

[46] Numerical Flow Analysis of the Impact Force from a Sphere Dropped in Air

○Takashi Nomura¹, Koutaro Watanabe², Junki Sakai³ (1.Department of Civil Engineering, College of Science and Technology, Nihon University, 2.Saitama Municipal Government, 3.Sumitomo Mitsui Construction Co., Ltd.)

Keywords:Fluid-structure interaction, FEM, Falling sphere, Impact force, Impulse

The present paper investigates the buckling and vibration behavior of cylindrical storage tanks based on wind tunnel experiments and FEM analysis. Focus is on the effect of the vibration of tank shells on the buckling behavior. The buckling loads obtained from the experiments are compared with those obtained from the FEM analysis for static wind loading. In the case of ring-stiffened tank models, the wind fluctuation affects the buckling
behavior. The extent and duration of large wind forces affect the buckling behavior significantly. On the other hand, in the case of free-edge tank models, the buckling mechanism is quite simple. The buckling occurs when the wind load become larger than buckling load. Therefore, the effect of the wind fluctuation on the buckling behavior is quite small. Finally, based on the results obtained from the wind tunnel experiments, the effects of wind fluctuation on the buckling behavior were estimated using the gust effect factor.