Investigation of Natural Modes with Changes in Harmonic Numbers along Axis of Thin Cylindrical Liquid Vessels

Abstract

This study investigates the circumferential modes of a thin cylindrical shell partially filled with liquid. Here two harmonic numbers appeared; one is above the liquid surface and the other one is below the surface. To clarify this phenomenon, we developed FEM code which can consider non-axisymmetric additional mass, additional stiffness, initial imperfection, and can express the above mentioned circumferential modes as its natural modes, too. We also carried out the vibration test with a small liquid shell by measuring vibrational modes in total tridimensional entire view. As a result, those modes are clarified to be the natural modes in the case that a cylindrical liquid shell has a non-axisymmetric additional mass, additional stiffness or initial imperfection. Analysis results by our original code could show good agreement with the experiment results, too.