In this work, we explore switchable acoustic scattering from underwater particles via instability-induced internal pattern transformation in the 50 kHz–80 kHz frequency range. Our wavelength scale aqueous scatterer is designed based on modeling using the finite element method for a square lattice of air-filled voids within a shape memory polymer and is directly 3D printed. The structure undergoes a buckling transformation when subjected to an external deformation while simultaneously being heated. Through computational and experimental results, we demonstrate that the deformation state change leads to programmable acoustic transparency, or opacity, for the scattering particle. Underwater propagation experiments resolved in the near field illustrate that the switchable acoustic characteristics are frozen in the structure with rapid cooling after compression, and the initial acoustic state can be automatically recovered through reheating.In this work, we explore switchable acoustic scattering from underwater particles via instability-induced internal pattern transformation in the 50 kHz–80 kHz frequency range. Our wavelength scale aqueous scatterer is designed based on modeling using the finite element method for a square lattice of air-filled voids within a shape memory polymer and is directly 3D printed. The structure undergoes a buckling transformation when subjected to an external deformation while simultaneously being heated. Through computational and experimental results, we demonstrate that the deformation state change leads to programmable acoustic transparency, or opacity, for the scattering particle. Underwater propagation experiments resolved in the near field illustrate that the switchable acoustic characteristics are frozen in the structure with rapid cooling after compression, and the initial acoustic state can be automatically recovered through reheating.

中文翻译：

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水声散射体中屈曲诱导的可重构性

在这项工作中，我们通过在 50 kHz-80 kHz 频率范围内的不稳定性引起的内部模式转换来探索水下粒子的可切换声学散射。我们的波长尺度水性散射体是基于使用有限元方法对形状记忆聚合物内的充气空隙方形晶格进行建模而设计的，并且是直接 3D 打印的。该结构在受到外部变形的同时受热时会发生屈曲转变。通过计算和实验结果，我们证明了变形状态的变化会导致散射粒子的可编程声学透明度或不透明度。近场解析的水下传播实验表明，可切换声学特性在压缩后快速冷却的结构中被冻结，并且通过重新加热可以自动恢复初始声学状态。在这项工作中，我们探索了水下粒子的可切换声学散射在 50 kHz–80 kHz 频率范围内不稳定引起的内部模式转换。我们的波长尺度水性散射体是基于使用有限元方法对形状记忆聚合物内的充气空隙方形晶格进行建模而设计的，并且是直接 3D 打印的。该结构在受到外部变形的同时受热时会发生屈曲转变。通过计算和实验结果，我们证明了变形状态的变化会导致散射粒子的可编程声学透明度或不透明度。近场解析的水下传播实验表明，在压缩后快速冷却的结构中，可切换的声学特性被冻结，通过再加热可以自动恢复初始声学状态。