粉・粒状物サイロの動的有効質量に関する実験的研究

Abstract

Forced vibration tests were performed with small-scale model silos on a shaking table in order to evaluate the dynamic effective mass during vibration of cylindrical silos used for storing granular materials. Four general conclusions were drawn I 1) For a given ratio of height to diameter (H/D), ranging from 0. 5 to 2.5, the measured resonance frequencies of a model silo filled with storage materials are 15-20 % those of the silo when it is empty. 2) As excitation acceleration amplitude increases, peak acceleration amplification values of contained material decrease and shift to lower frequencies. This was also mathematically simulated by a numerical analysis which expressed the shear modulus and damping ratio as a function of strain. 3) Resonance frequencies of silos are proportional to the square root of extensional rigidity, independent of the type of fill material. This is approximated by the vibration of a continuous solid when a silo's H /D is less than 3. 4) When a silo's extensional rigidity is below a certain constant value, the coefficient of dynamic effective mass is unity. If H/D>1.5, this coefficient is approximately 1.0, and if H/D<1, the coefficient is approximately 0.5-1. 0.