Abstract: The multiple scattering of sound waves and the fluid-structure interaction should be taken into account to calculate the acoustic scattering of underwater elastic corner reflectors. The scattering acoustic field of underwater elastic corner reflectors in far field is simulated by using structure finite element method (FEM)/fluid indirect coupled boundary element method (IBEM). The influences of plate material and thickness, incident angle and the type of corner reflector on target strength and the scattering mechanism are analyzed when the incident wave frequency varies from 5.0 kHz to 20.0 kHz. The results show that the scattering acoustic field of underwater elastic corner reflectors has a strong frequency characteristic. It varies with plate material and thickness,and incident wave frequency. The multiple scattering of sound waves has important contributions to the backscattering acoustic field of corner reflectors. The simulated results are in good agreement with the experimental results. The structure design and optimization method of corner reflectors are presented. Key

Key words: underwaterelasticcornerreflector, indirectboundaryelementmethod, scatteringacousticfield, fluid-structurecoupling