Natural frequency response of vertical cantilever composite shells containing fluid

摘要

An analytical investigation of the natural frequency response of multi-layered orthotropic circular cylindrical shells partially sub- merged in or filled with non-viscous incompressible fluid has been developed here. The typical examples could be of liquid storage tanks or vertical pipe conveying fluid or submerged in fluid. Since these shells are considered to be laminated of composite material, the effect of transverse shear deformation and rotary inertia terms have been taken into account in the analysis. Axial dependence of modal forms is assumed in the form of a simple Fourier series instead of the commonly used exponential axial dependence. A modified variational method is used here to obtain a polynomial frequency equation. This equation can be solved for an arbitrary choice of end conditions. As an illustration the important case of a vertical cantilever shell with bottom end clamped and top end free is considered and analyzed in detail. The effect of variation in the fluid height level on the frequency response is studied. The influence of axial and meridional stiffnesses of the shell on the natural frequencies is also discussed.