Impact Vibration Analysis of Group of Hexagonal Bars Immersed in Liquid

摘要

A simulation method was developed to calculate the vibrational response of a group of hexagonal bars installed in a restraint immersed in liquid during seismic excitation. The influence of fluid force on structural motion was modeled using an added-mass matrix. This matrix was then transformed into the space composed of the eigenmodes of the hexagonal bars without added mass and used for eigenvalue analysis of the entire bar-group structure. This method reduced the computational time needed for practical added-mass matrix calculation and the eigenvalue analysis. It was shown that the proposed method yielded almost the same eigenvalues as the conventional method conducted in standard physical space. Added-mass models for use in impact-vibration analysis were investigated using the proposed method. Comparing the results calculated using the proposed method with those calculated using concentrated added mass, which is a simplified model, showed that the latter can be used for a rough response calculation, while the precise calculation requires the added-mass matrix method.