In order to investigate the characteristics of the vibration and sound field radiated by a cylindrical stiffened shell with two spherical end caps, a 3D model of finite element-boundary element method for computing the sound field radiated by an axisymmetric shell with stiffening rings in water has been established, and the effects of the height, the width and the number of the ring stiffeners on the RMS (root mean square) vibratory velocity, sound radiated power, radiation efficiency, normal sound intensity at driving point and pressure directivity of sound field radiated by it have been investigated. The data of the model in vacuum obtained from finite element methods code Ansys are put into boundary element methods code Sysnoise and used for computing the parameters of the coupled sound field. The results show that the curve peaks of the RMS vibratory velocity, radiated sound power, radiation efficiency, normal sound intensity at driving point will shift to different places when the width , or the height or the number of the stiffening rings increases. With the increase of the width , or the height or the number of the stiffening rings, the normal sound intensity at driving point and sound radiated power increase, the RMS vibratory velocity decreases ,and the radiation efficiency increases. In the frequency region 0～800 Hz ,the influence of the width and the height of the rings on the sound field directivity pattern are nearly same.

stiffening ring; axisymmetric shell; characteristics of vibration and sound field