Influence of Rib Strengthening on Structure Vibration and Sound Radiation of Cylindrical Shell

An approach combining FEM with BEM is adopted to calculate the structural vibration and sound radiation of an underwater cylindrical shell. By using FORTRAN codes to compute the added mass and added damping matrices, DMAP codes to add them to structural mass and damping matrices, the problem of fluid-structural interaction was solved. Through comparing the mean square normal velocity level and sound radiation power level of ring-stiffened cylindrical shell with different inertia moment of stiffeners, the results can be acquired: with the moment of inertia gets bigger, the peak frequency of the frequency-response curves increases while the peak value of vibration and sound radiation decreases. The number of strengthened stiffeners has the same effect on peak frequency as the moment of inertia, but has no effect on peak value.