Advanced Impact Resistant Auxetic Materials via Additive Manufacturing

伸展材料，通常被称为“超材料”或“负泊松比材料”，它们对变形的反应是违反直觉的。当它们被拉伸时，它们会膨胀，反之，它们在压缩时会收缩。这种行为使它们对冲击应用非常有吸引力；在以高速率压缩加载时，它们往往会提供更大的阻力。因此，目前有几种商业伸展产品可供选择，特别是由世界最大制造商生产的运动鞋。 然而，随着加法制造(AM)的到来，延展材料的更广泛应用才引起了人们的极大关注。AM是一种制造方法，在这种方法中，可以从各种材料中打印出非常复杂的几何图形。最近，AM已被应用于植入剂的制造，目的是利用AM的优势，即打印弯曲和分级材料的能力。然而，目前的努力仅限于相对较小的尺寸和/或尚未在规模上进行实验测试。需要一种设计工具来弥合实验室规模的AM辅助技术和工程辅助商业产品之间的技术差距，这些产品具有大尺寸(大约几十厘米)。 这项拟议工作的短期目标是开发一种经过验证的设计工具，可以虚拟地模拟拉伸材料。需要这种设计工具来加速针对Impact应用的延伸性产品的开发。长期目标是利用AM的优势来解决众所周知的冲击防护装备不平等问题，在这种情况下，女性专用运动鞋和弹道防弹衣是众所周知的需求。由于针对性别的产品的制造成本很高，这些需求目前得到了非常稀少的满足。通过使用拟议的设计工具，这项工作旨在提供一种技术手段，以加快这些需要的鞋类和装甲产品的开发，使其更加切合实际。

Auxetic materials, often referred to as “metamaterials” or “negative Poisson's ratio materials”, are counter-intuitive in their response to deformation. Upon being stretched they will expand and conversely will contract when compressed. This behavior makes them very attractive for impact applications; upon being compressively loaded at high rates they will tend to supply increased resistance. As such there are several commercial auxetic products currently available, notably athletic footwear produced by the world's largest manufacturer. However, broader application of auxetic materials is only now garnering significant attention with the advent of additive manufacturing (AM). AM is a manufacturing method in which very complex geometries can be printed out of a wide variety of materials. Recently, AM has been applied to the manufacture of auxetics with the aim of leveraging the advantages of AM, namely the ability to print curved and graded materials. However, the current efforts have been limited to relatively small sizes and/or have not been experimentally tested at scale. A design tool is needed to bridge the technology gap between lab-scale AM auxetics and engineering auxetic commercially-ready products that have large sizes (on the order of tens of centimeters). The short-term objectives of the proposed work is to develop a validated design tool that can virtually simulate auxetic materials. This design tool is needed to accelerate the development of auxetic products for impact applications. The long-term objective is to harness the advantages of AM to address a well-known inequality in impact protective gear where female-specific athletics footwear and ballistic body armor are well-known needs. These needs are currently very sparsely filled due to the high manufacturing costs for sex-specific products. Through the use of the proposed design tool, this work aims to provide a technological means of accelerating the development of these needed footwear and armor products more realistic.