I-Corps: Auxetic Structures for Practical Applications

该I-Corps项目更广泛的影响/商业潜力在于为开发适用于广泛应用的拉胀复合材料提供框架（拉胀材料当沿其长度沿着拉伸时，在宽度方向上变得更厚，当纵向压缩时变得更薄）。这个项目有可能成为关键的方式，拉胀材料的研究，设计和制造。商业潜力跨越几个不同的行业，其中寻求改进的抗冲击性、抗压痕性、能量和声音吸收性能以及同向弯曲。最大的商业影响将是在需要这些性能的组合应用中，包括个人防护设备，以及汽车和航空航天领域的结构和噪声与振动应用。I-Corps项目的重点是开发负泊松比（即拉胀）复合材料，以满足广泛的商业应用。 该技术的动机是拉胀材料的许多有吸引力的机械性能。 在理论上，负泊松比材料具有比具有正泊松比的材料更高的硬度、抗冲击性、断裂韧性、吸声性能和剪切模量。 此外，拉胀材料在弯曲时表现出同向曲率，这意味着它们可以弯曲成双弯曲形状，从而消除了制造弯曲或圆顶形部件所需的一些机加工。由于大多数目前可用的拉胀材料和结构是多孔的并且具有低刚度，实际的结构应用在很大程度上仍然是难以捉摸的。 该项目代表了一条直接通往利用拉胀材料的商业应用的结构的路线。该方法的独特之处在于使用折纸模式，折叠时表现出拉胀行为，以告知一类新的负泊松比结构的设计和开发。这些结构可以通过折叠和/或增材制造来实现，其中材料和长度尺度选择基于具体应用。

The broader impact/commercial potential of this I-Corps project lies in the contribution of a framework for the development of auxetic composites that are suitable for a broad range of applications (an auxetic material, when stretched along its length, becomes thicker in width-wise directions and it becomes thinner when compressed lengthwise). This project has the potential to be pivotal in the way that auxetic materials are studied, designed and fabricated. The commercial potential spans several different industries where improved impact resistance, indentation resistance, energy and sound absorption properties, and synclastic curvature are sought. The greatest commercial impacts will be in applications requiring a combination of these properties, including personal protective equipment, and structural and noise and vibration applications in the automotive and aerospace sectors.This I-Corps project is centered on the development of negative Poisson's ratio (i.e. auxetic) composites for a wide range of commercial applications. The technology is motivated by the many attractive mechanical properties of auxetic materials. In theory, a negative Poisson's ratio material has improved hardness, impact resistance, fracture toughness, sound absorbing properties, and shear modulus over one with a positive Poissons ratio. In addition, auxetic materials exhibit synclastic curvature when bent, which means that they can be bent into a doubly curved shape, thus eliminating some of the machining necessary to fabricate curved or dome-shaped parts. Since most currently available auxetic materials and structures are porous and have low stiffness, practical structural applications remain largely elusive. This project represents a direct route to structures that exploit the benefits of auxetic materials for commercial applications. The uniqueness of the approach lies in the use of origami patterns which exhibit auxetic behavior when folded to inform the design and development of a new class of negative Poisson's ratio structures. Those structures can be realized through folding and/or additive manufacturing, with the material and length scale selection based on the specific application.