The advent of additive manufacturing (AM) has enabled topological control of structures at the micrometer scale, transforming the properties of polymers for a variety of applications. Examples include tailored mechanical responses, acoustic properties, and thermal properties. Porous polymer materials are a class of materials used for shock and blast mitigation, yet they frequently possess a lack of structural order and are largely developed and evaluated via trial-and-error. Here, we demonstrate control of shockwave dissipation through interface-dominated structures prepared by AM using 2-photon polymerization. A fractal structure with voids, or free surfaces, arranged less than 100 μm apart, allows for rarefaction interactions on the timescale of the shockwave loading. Simulations and dynamic x-ray phase contrast imaging experiments show that fractal structures with interfaces assembled within a “critical” volume reduce shockwave stress and wave velocity by over an order of magnitude within the first unit cell.

中文翻译：

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界面主导的多孔结构消散冲击波

增材制造（AM）的出现使微米级结构的拓扑控制成为可能，从而改变了聚合物在各种应用中的性能。示例包括定制的机械响应，声学特性和热特性。多孔聚合物材料是用于减震和减震的一类材料，但是它们通常缺乏结构秩序，并且经过反复试验而得到大量开发和评估。在这里，我们演示了通过使用2光子聚合通过AM制备的界面主导结构控制冲击波消散的方法。具有空隙，或自由表面，分形结构布置小于100 μ两者之间的距离允许在冲击波加载的时间尺度上进行稀疏相互作用。仿真和动态X射线相衬成像实验表明，在“临界”体积内组装界面的分形结构在第一个晶胞内将冲击波应力和波速降低了一个数量级。