水下加筋圆柱壳结构声散射特性研究

采用有限元/边界元(FEM/BEM)方法对水下加筋圆柱壳结构的声散射特性进行分析。考虑入射声场激发弹性结构振动产生二次辐射声场,总声场为入射场与散射场之和。基于Mindlin理论建立结构受迫振动的有限元模型,考虑入射声场为简谐激励,采用模态叠加法求出结构振动表面速度。根据声学边界元相关理论,利用有限元方法计算得出的弹性结构表面动力相应,可求出弹性结构的散射声场。研究结果表明,在同一波数下,不加筋结构后向散射强于加筋结构;加筋结构的散射指向性图案分叉较为明显;同种结构在波数增加的时候后向散射强度逐渐增大,前向散射强度逐渐减弱。

Study on the Acoustics Scattering of a Submerged Stiffened Cylindrical Shell Structure

This paper introduces the use of the finite element/boundary element method for analysis of the acoustics scattering of submerged stiffened cylindrical shell structures.The structure is excited by incident wave and radiates energy.The sound field totals incident field and scattering field.Base on the Mindlin theory,forced vibration finite element model of the structure is established,and then the finite element method is used to calculate the dynamic surface response of a structure.Base on the theory of boundary element method in acoustics,using the dynamic surface response of a structure calculates the scattering field.The result of this study show that the back scattering of structure without stiffened is stronger than stiffened one,in the same wave number;stiffened structure scattering directivity patterns has more distinct bifurcation;with the increasing in wave number,the back scattering intensity gradually increases,and the forward scattering intensity gradually diminish.