A comparison of experimental and theoretical vibration results for fluid-coupled, co-axial cylinder

A fluid-coupled cylinder under seismic loading reveals a much more complex behavior than was implied by design assumptions. The problem becomes more complex when two coaxial cylinders were coupled by water in their adjacent annular region such as pressure-suppression pools in Boiling Water Reactors. Theoretical and experimental investigations of the vibrational behavior of a cylindrical shell and coaxial cylinder were conducted to seek possible improvements in the design. The study is carried out in two steps. 1. Test on the shaking table. Two models are used in this test. One is a cylindrical shell, and other is coaxial cylinder which has the fluid filled annular space. The model was set up on the shaking table and excited with sinusoidal wave. The natural frequencies, mode shapes, and hydrodynamic pressure distributions were measured. Tests were conducted at several water level. 2. A theoretical treatment of the liquid-shell systems. This study includes the development of a general finite element theory for axisymmetric shell, and computer code to implement finite element theory. This program compute the natural frequencies, mode shapes, and hydrodynamic pressure distributions including the initial hoop stress due to the hydrostatic pressure. (orig./GL)