The behavior of porous materials under shock loading is a multi-scale problem bridging orders of magnitude across the macroscale geometry and the microscale pores. Under static loading, this problem is well understood, relating mechanisms of pore closure and crushing to the equivalent macroscale models. The dynamic response of porous solids under shock loading is related to the effects of viscoplasticity and micro-acceleration fields around the void boundaries. The significance of the micro-inertia effects in modeling the dynamic behavior of porous materials remains an open question. In this work, an experimental investigation on closed-cell porous aluminum with small porosity provides the evidence for the first time of micro-inertia's fundamental role in describing the shock structure in these materials. Materials with different levels of porosity were manufactured using a modified process of additive manufacturing to achieve a mean pore size below 50μm. Plate impact experiments on porous aluminum samples were conducted at pressures in the range of 2 to 11 GPa. The structure of the steady shock was characterized as a function of porosity and shown to validate behavior revealed by an analytical approach (Czarnota et al. [J. Mech. Phys. Solids 107 (2017)]), highlighting the fundamental role of micro-inertia effects in such cases.

多孔材料在冲击载荷下的行为是跨越宏观几何和微观孔隙的跨数量级的多尺度问题。在静态载荷下，这个问题很好理解，将孔隙闭合和破碎机制与等效的宏观模型相关联。该动态多孔固体在冲击载荷下的响应与空隙边界周围的粘塑性和微加速度场的影响有关。微惯性效应在模拟多孔材料的动态行为中的重要性仍然是一个悬而未决的问题。在这项工作中，对具有小孔隙率的闭孔多孔铝的实验研究首次提供了微惯性在描述这些材料的冲击结构中的基本作用的证据。使用改进的增材制造工艺制造具有不同孔隙率水平的材料，以实现低于 50μm 的平均孔径。在 2 到 11 GPa 范围内的压力下对多孔铝样品进行板冲击实验。