A semi-analytical method is developed for vibration and acoustic analysis of a submerged ring-stiffened cylindrical shell coupled with arbitrary inner structures. The whole structure is firstly disassembled into the stiffened cylindrical shell and inner structures, which are respectively analyzed through analytical substructure method and numerical approach. For the analytical substructure method, the cylindrical shell is decomposed into several shell segments according to positions of stiffeners and external forces, including exciting forces and coupling forces. These shell segments are described by Flügge shell theory and the ribs are governed by the annular plate equations. The solutions for cylindrical shell segments and rings are expanded as wave functions and Bessel functions. For the inner structures with arbitrary irregular shapes, finite element method (FEM) is utilized to establish their motion equations. At each coupling node, an artificial spring is adopted to connect the shell and inner structures, so rigid and elastic coupling conditions can be easily simulated by setting different stiffenesses to these springs. For external fluid field, an axisymmetric boundary element method (BEM) is employed to calculate the acoustic pressure. Combining the displacement continuity and force balance conditions at the joints of adjacent shell segments and introducing the coupling forces derived from inner structures and the fluid loading, the vibro-acoustic equations of the coupled system are obtained. To verify the validity of the present approach, vibro-acoustic responses of the semi-analytical method are compared with the ones calculated through FEM/BEM. Furthermore, effects of the coupling stiffness between the shell and inner structures and external fluid loading on vibro-acoustic responses are also evaluated.

开发了一种半分析方法，用于对带有任意内部结构的浸入式环形加筋圆柱壳进行振动和声学分析。首先将整个结构分解为加劲的圆柱壳和内部结构，分别通过解析子结构方法和数值方法进行分析。对于分析子结构方法，根据加劲肋的位置和外力（包括激振力和耦合力），将圆柱壳分解为几个壳段。这些壳段由Flügge壳理论描述，肋由环形板方程控制。圆柱壳段和环的解扩展为波动函数和贝塞尔函数。对于具有任意不规则形状的内部结构，利用有限元方法（FEM）建立其运动方程。在每个耦合节点处，都采用了人造弹簧来连接壳体和内部结构，因此可以通过为这些弹簧设置不同的刚度来轻松模拟刚性和弹性耦合条件。对于外部流体场，采用轴对称边界元法（BEM）来计算声压。结合相邻壳段连接处的位移连续性和力平衡条件，并引入内部结构和流体载荷所产生的耦合力，得到了耦合系统的振动声方程。为了验证本方法的有效性，将半分析方法的振动声响应与通过FEM / BEM计算的响应进行了比较。此外，