摘要:
研究内部真空周期性加隔板圆柱壳在水中的声散射特性. 壳体振动用薄壳理论的Donnell方程描述, 隔板振动用相互独立的薄板纯弯曲振动和平面应力状态下的振动方程描述. 考虑轴向、切向、径向三个方向的力和弯矩共同作用导出了散射声场的解析表达式. 数值计算给出远场收发合置情况下的角度-频率谱图, 并据此进行机理分析. 通过与内部周期性加环肋圆柱壳声散射的角度-频率谱图比较发现, 除周期加肋产生的Bragg散射波与弯曲Bloch-Floquet波外, 加隔板的情况还存在明显的隔板共振亮线, 并且发生隔板共振与壳体弹性波、 Bragg散射波、弯曲Bloch-Floquet波耦合的现象. 通过实验对理论进行了验证, 在实验的频率范围内, Bragg散射亮线与理论符合得很好, 部分Bloch-Floquet波散射亮线和隔板共振散射亮线也与理论符合.
Abstract:
Acoustic scattering from a submerged finite cylindrical shell with periodically bulkheads, insonified by an incident plane wave, is studied. The motion of shell is described by Donnell equations, while the motion of bulkheads is described by thin plate motion equations and plane stress equations with considering axial force circumferential force radial force and bending moment simultaneously. Through angle-frequency spectrum besides the surface elastic waves, Bragg waves and Bloch-Floquet waves for the periodically bulkheads, the interactions between bulkheads resonance can be seen. Finally the theory is verified by experiment. Bragg waves, partial Bloch-Floquet waves and resonance of bulkheads highlight are all accordant with theory.
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