含周期性空腔结构吸声机理的研究

为了研究水下含周期性空腔结构的吸声机理,建立并验证了含轴对称空腔周期性结构吸声特性计算的简化有限元仿真方法,用简化的有限元模型结合遗传算法对水下环境含周期性圆柱空腔结构的吸声性能进行了优化设计.从能量耗散、变形和模态的角度分析了含周期性空腔结构的吸声机理.空腔结构谐振包括表层的弯曲振动和空腔附近的径向变形,且径向运动也...

Sound-absorption mechanism of structures with periodic cavities

A simplified FEM simulation method has been established and validated for analyzing the sound absorption mechanism of periodic structures with axisymmetric cavities. Combined with genetic algorithm, the simplified FEM method is used to optimize the sound absorption coefficient of the structure containing periodic cylindrical cavities. Through energy dissipation, deformation and modal analysis of the optimized absorption structure, it is found that the cavity structure resonances include bending vibration of the surface layer and radial motion of particles near the cavities. The radial motion also changes with the thickness direction of the structure. The bending vibration modes of the surface layer are mainly and easily excited at relatively low frequencies and the radial motion modes are mainly excited at relatively high frequencies. The radial vibration has a great influence on absorption performance, which is more conducive to promoting the conversion of longitudinal waves into transverse waves with more energy dissipation.