Auxetic Blast Protection Textiles -Crime Feasibility Study

这项建议涉及一项研究，旨在研究基于埃克塞特大学最近开发的螺旋拉伸纱线所表现出的极不寻常的特性，构建防爆纺织品的可行性。伸展材料是指泊松比为负的材料，(N)。这意味着，与拉伸时变薄的传统材料(泊松比为正值)不同，伸展材料会变得更胖。这种不同寻常的行为可以被用来建造能够以以前不可能实现的方式工作的结构。这项研究将集中于进一步开发和利用具有伸展几何的螺旋纤维丛的性质。埃克塞特开发的束显示了从零应变到全应变的伸展功能；伸展效应的大小也远远超过了这一点。还可以使用传统的织物编织技术大量生产这些束。这些功能将使AUXTICATION的独特特性能够在商业应用中得到利用--最初是在开发新一代智能防爆面料时。炸弹爆炸网窗帘的发明是为了减少与爆炸事件相关的危险。玻璃通常是建筑物最薄弱的部分，在低压下破裂。在一次大爆炸后，玻璃碎片可以延伸数英里，高速玻璃碎片是此类事故中受伤的主要原因。通常情况下，在爆炸中受伤的人比死亡的人多得多。通过为潜在目标提供窗户保护，撕裂伤害显著减少。目前的防风帷幕设计倾向于使用芳纶网。当爆炸发生时，窗帘的设计是为了卷起并捕获很大一部分玻璃碎片。然而，在实践中，网布经常被爆炸的力量撕裂。这是因为网丝必须做得很细，以防止窗帘挡住光线。我们需要的是一种智能纺织品，既能让光线穿透，又能遏制爆炸中的巨大力量，并为碎片的飞行提供障碍。该项目旨在研究不同的拉伸织物和织物对爆炸波的反应，以及这种行为在多大程度上可以用来减轻爆炸的影响。这项研究的目的是最终完成几种试生产原型纺织品的设计、制造和测试。膨胀性纺织品有几个潜在的用途。一种解决方案是，在拉长的开放式单元结构中部署智能辅助织物，这种结构将是半透明的，使窗帘能够随时使用。如果发生爆炸，窗帘编织会被最初的冲击波触发坍塌，织物会收缩，导致织物更紧密，这将对玻璃和其他飞来的碎片构成有效的屏障。或者，可以利用这些纱线来创造一种层叠纺织品，通过在每一层中打开阵列的气孔来响应冲击波锋面的开始。这让爆炸波从一层传到下一层，连续地分散了它携带的能量。这种纺织品不仅是阻挡碎片飞行的屏障，而且还能减弱最初爆炸冲击波的影响。可以改变基本设计中的不同参数，以改进系统--包括纤维缠绕角度、纤维直径和所用材料的基本特性。研究中使用的方法将是遵循项目工作方案，将其分解为一系列工作包，使用里程碑来侧重活动和衡量进展情况。埃克塞特和AUXTYING有限公司将负责整个研究工作的主体。HeathCoats Ltd将参与织造测试和试验面料的生产，PSDB将对候选纺织品进行最终喷砂测试。

This proposal concerns a study to examine the feasibility of constructing a blast-protection textile based on the highly unusual properties exhibited by helical auxetic yarns recently developed at the University of Exeter. An auxetic material is one which has a negative Poisson's ratio, (n). This means that, unlike conventional materials (with a positive Poisson's ratio) that get thinner when stretched, an auxetic material will get fatter. This unusual behaviour can be exploited to construct structures which can work in ways that have not previously been possible. This study will focus on further developing and exploiting the properties of helical fibre bundles with an auxetic geometry. The bundles developed at Exeter show auxetic functionality from zero to full strain; where the magnitude of the auxetic effect is also far superior. The bundles can also be produced in large quantities using conventional fabric weaving techniques. These features will enable the unique properties of auxetics to be utilised in a commercial application, - initially in the development of a new generation of smart blast protection fabrics. Bomb blast net curtains were invented for reducing hazards associated with explosion incidents. Glass is often the weakest part of a building, breaking at low pressures. Breakage can extend for many miles after a large explosion, and high velocity glass fragments are a major contributor to injuries in such incidents. Typically, many more people are hurt in explosions than are killed. By providing potential targets with window protection, laceration injuries are significantly reduced. Current blast curtain design favours the use of aramid nets. When an explosion occurs, the curtains are designed to billow out and capture a significant portion of the glass fragments. However in practice, the net fabric is often torn by the force of the blast. This is because the net filaments have to be made thin to keep the curtain from blocking light out. What is needed is a smart textile that allows light through but is also capable of containing the huge forces involved in an explosion and provides a barrier to flying debris. The project aims are to research how different auxetic fabrics and weaves respond to blast waves, and how far this behaviour can be used to mitigate the effects of explosions. It is intended that the study will culminate in the design, manufacture and test of several pre-production prototype textiles. There are several potential uses for auxetic textiles. One solution would involve the deployment of a smart auxetic fabric in a stretched open cell arrangement that would be translucent, enabling the curtains to be used at all times. In the event of an explosion, the curtain weave would be triggered to collapse by the initial shock wave, the fabric would shrink in resulting in a much tighter textile that would present an effective barrier to glass and other flying debris. Alternatively these yarns can be exploited to create a laminated textile which responds to the onset of a blast front by opening up arrays of pores in each layer. These let the blast wave pass through from one layer to the next, successively dispersing the energy it carries. Such textiles would not only be barriers to flying debris but also act to diminish the effects of the initial blast shock wave. Different parameters within the basic design may be altered to allow the system to be refined - these include fibre winding angles, fibre diameters and the basic characteristics of the materials used. The methodology used in the study will be to follow a project work programme broken down into a series of work packages, using milestones to focus activity and measure progress. Exeter and Auxetics Ltd will be responsible for the main body of research work throughout. Heathcoats ltd will be involved in weaving tests and the production of trial fabrics, and the PSDB will conduct the final blast testing of candidate textiles.