Designing protective armors is important for varied civil and defense applications. Ceramic-polymer composite armors are particularly interesting for their high strength and light weight with high energy absorption capability. While the function of ceramic is to retard ballistic impact penetration, polymer panel serves the purpose of absorbing high energy generating from the propagating elastic/stress waves. Enhancing this energy absorption capability of the armor is essential for its back face signature. Our present study shows that the energy absorption can be considerably enhanced if the bulk polymer panel is replaced with a polymer based metamaterial. To demonstrate this, a comparison of the polymer metamaterial is made with its solid counterpart, i.e., bulk polymer matrix in terms of their respective transmission losses in the propagating elastic waves. We have also studied the effect of size of the polymer metamaterial, e.g., by increasing the number of metamaterial layers and variation in the the fiber length and thickness within a layer. A major challenge in such studies is the extreme computational overhead involved in solving continuum mechanics equations using finite element methods on the complex geometry with microstructure details. Note that microstructure details, i.e., geometry, size and shape are mostly responsible for the nonintuitive properties of metamaterials. We have bypassed the huge computational requirement by proposing a novel coarse-grained methodology based on energetics of the structure for the polymer metamaterial. We envisage that the methodology would be useful to other related studies on mechanical metamaterials.

中文翻译：

---

设计用于防护装甲的聚合物超材料：粗粒度配方

设计防护装甲对于各种民用和国防应用很重要。陶瓷聚合物复合装甲因其高强度、轻质和高能量吸收能力而特别受关注。虽然陶瓷的功能是阻止弹道冲击穿透，但聚合物面板的作用是吸收传播弹性/应力波产生的高能量。增强盔甲的这种能量吸收能力对于其背面签名至关重要。我们目前的研究表明，如果将本体聚合物面板替换为基于聚合物的超材料，则可以显着提高能量吸收。为了证明这一点，将聚合物超材料与其固体对应物进行比较，即，块状聚合物基体在传播的弹性波中各自的传输损耗。我们还研究了聚合物超材料尺寸的影响，例如，通过增加超材料层的数量以及层内纤维长度和厚度的变化。此类研究的一个主要挑战是在具有微观结构细节的复杂几何体上使用有限元方法求解连续介质力学方程所涉及的极端计算开销。请注意，微观结构的细节，即几何形状、尺寸和形状，主要是造成超材料的非直观特性的原因。我们提出了一种基于聚合物超材料结构能量学的新型粗粒度方法，绕过了巨大的计算需求。