Collaborative Research: Design of Negative Stiffness Metamaterials

合作研究：负刚度超材料的设计

• 批准号: 1435548
• 负责人: Carolyn Seepersad
• 金额: $ 43万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-01 至 2018-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1435548&HistoricalAwards=false
• 关键词: Collaborative; Research; Design; Negative; Stiffness

Engineers frequently face a critical selection decision between materials with high structural stiffness and materials with superior damping capabilities. Existing materials cannot provide both capabilities simultaneously. This award supports fundamental research to break this tradeoff by designing negative stiffness (NS) metamaterials. These materials gain their properties from their internal structure, which includes micro-scale structures that snap back and forth to absorb energy - a phenomenon called negative stiffness. Novel top-down design strategies developed in this project will allow engineers to quickly identify the material designs that meet performance goals as closely as possible. Negative stiffness metamaterials will benefit a variety of applications of great interest to society, such as stiff, low-vibration wind turbine blades and rotors and sonar mounts for submarines. The research involves graduate and undergraduate students, educational outreach activities, and a minority-serving institution, which will help broaden the participation of underrepresented groups and positively impact engineering education. The research team will design these materials with a novel, top-down design exploration strategy for quickly and efficiently back-propagating application-specific, system-level performance requirements to the characteristics of the micro-scale material structure. This top-down strategy contrasts with trial-and-error, bottom-up strategies that cycle through multiple material structures in search of satisfactory system-level performance. The top-down design exploration strategy utilizes Bayesian network classifiers for mapping structure-property relationships at each level of the multi-level design problem in such a way that the maps can be intersected across levels to identify good multi-level designs and also efficiently guide the search for better designs. The design exploration strategy is coupled with three levels of material models, ranging from (a) the micro-scale level on which the geometry and fabrication route for the snap-through inclusions must be designed to provide negative stiffness behavior to (b) the meso-scale level on which the distribution of inclusions in a ductile matrix must be designed to provide targeted effective material properties to (c) the macro-scale level of a component, which must be designed along with the metamaterial to provide targeted structural stiffness and damping. Materials design and modeling efforts will be validated by additively manufacturing micro-scale inclusions using microstereolithography, embedding them in a matrix material, and testing the resulting composite to determine the overall dynamic structural stiffness and loss characteristics. A collaboration with an industrial partner will pave the way for applications of the NS metamaterials in challenging military and commercial applications.

工程师经常在具有高结构刚度的材料和具有出色阻尼功能的材料之间面临关键的选择决策。 现有材料不能同时提供两种功能。 该奖项支持基本研究，通过设计负刚度（NS）超材料来打破这种权衡。 这些材料从内部结构中获得了它们的特性，其中包括微型结构来回捕捉能量 - 一种称为负刚度的现象。 该项目中开发的新型自上而下的设计策略将使工程师能够快速确定尽可能紧密地满足性能目标的材料设计。 负刚度超材料将使社会引起人们极大的兴趣应用，例如僵硬，低振动的风力涡轮机叶片，转子和声纳式坐骑，用于潜艇。 该研究涉及毕业生和本科生，教育外展活动以及少数派服务机构，这将有助于扩大代表性不足的团体的参与并积极影响工程教育。 研究团队将通过一种新颖的自上而下的设计探索策略来设计这些材料，以快速有效地向后传播特定的系统级性能要求，以符合微型材料结构的特征。 这种自上而下的策略与反复试验的自下而上的策略形成鲜明对比，这些策略通过多种材料结构循环，以寻找令人满意的系统水平性能。 自上而下的设计探索策略利用贝叶斯网络分类器在多层设计问题的每个层面上绘制结构 - 特性关系，以使地图可以跨级别相交以识别良好的多层设计并有效地指导搜索更好的设计。 设计探索策略与三个级别的材料模型相结合，范围从（a）必须设计的几何形状和制造途径，以提供负面僵硬的行为，以提供负面刚度的行为到（b）（b）在（b）中等级别的含量级别的含量级别的含量级别的含量（b）含有有效的物质的内部尺度级别，以便有效的材料级别的材料级别，即与超材料一起设计以提供靶向的结构刚度和阻尼。 材料设计和建模工作将通过使用微骨术，将它们嵌入基质材料中，并测试所得复合材料以确定整体动态结构僵硬和损失特性，从而验证材料设计和建模工作。 与工业合作伙伴的合作将为NS超材料在具有挑战性的军事和商业应用中的应用铺平道路。