水下多格弹性角反射体声反射特性及强度增强方法

Acoustic Reflection Characteristics and Strength Enhancement Method of Underwater Multigrid Elastic Corner Reflector

单格角反射体只能反射一定方向的入射波,为了反射不同方向入射声波,需要构造多格角反射体并研究其声反射特性。以不同类型八格金属板角反射体为对象,基于结构有限元耦合间接边界元法,对水下多格弹性角反射体的散射声场进行数值仿真,分析不同频率、材料、厚度、入射角度等因素影响下不同类型多格角反射体声反射性能,从便于工程应用角度提出增强其声反射能力的方法。通过典型情况下的水池实验,对仿真计算与实验数据的一致性进行验证。实验结果表明:水下多格弹性角反射体目标强度随入射频率增大而增大,并趋向稳定;目标强度随入射角度改变波动幅度较大,不同类型角反射体目标强度值差异较大;目标强度随平板厚度的增加而增大,但不显著;目标强度随着边长的增加而明显增大;软介质材料构成的多格角反射体,水下声反射性能明显优于金属角反射体。因此,为增强水下多格角反射体声反射能力,增大反射体边长及选用低阻抗材料是更有效的方法。

Single grid corner reflector can only reflect the incident wave in a certain direction.In order to reflect the incident acoustic waves in different directions,it is necessary to construct a multigrid corner reflector and study its acoustic reflection characteristics.Taking the different types of eight-grid corner reflectors as the research object,the scattering acoustics field of underwater multigrid corner reflectors is simulated based on the structure finite element coupled indirect boundary element method.The acoustic reflection performance of different types of multigrid corner reflectors under the condition of different frequencies,materials,thicknesses,and incident angles is analyzed.A method to improve its acoustic reflection ability is proposed from the perspective of convenient engineering application.The consistency between the simulation data and the experimental data is verified through the experiment in a pool under typical conditions.The results show that the target strength of underwater multigrid elastic corner reflector increases with the increase in the incident frequency and tends to be stable;the target strength fluctuates greatly with the change of incident angle,and the target strength values of different types of corner reflectors are greatly different;target strength increases with the increase of plate thickness,but not significantly;the target strength increases obviously with the increase in the side length;and the acoustics reflection performance of multigrid corner reflector made of soft material is better than that of metal corner reflector.Therefore,in order to enhance the acoustic reflection ability of underwater multigrid corner reflector,it is more effective to increase the side length of reflector and select low impedance material.