Understanding stress focusing in thin solids in the absence of tensile loads

了解在没有拉伸载荷的情况下薄固体中的应力集中

基本信息

批准号：
2318680
负责人：
Joseph Paulsen
金额：
$ 47.51万
依托单位：
Syracuse University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2023
资助国家：
美国
起止时间：
2023-07-01 至 2026-06-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2318680&HistoricalAwards=false
关键词：
Understanding stress focusing thin solids

项目摘要

Nontechnical AbstractThin materials can be bent, twisted, and wrinkled into a multitude of forms. The resulting shapes can be smooth like the undulating edge of a flower, or sharp like the creases and points in a crumpled ball of foil. The goal of this research is to understand when these features turn out to be smooth versus when they are sharp. This deceptively simple question is surprisingly difficult to answer, and it impacts a variety of technologies that rely on thin sheets. This project consists of a suite of model experiments where polymer films are forced into different geometries, forcing them to buckle. Because the project focuses on physical behaviors that should be scale-free, our discoveries should be applicable to material systems ranging from the very small to the very large, from graphene films to food packaging to deployable satellites. The research is coupled to a set of education and outreach projects that target a wide range of audiences. The project will train two PhD students who will work with undergraduates and high school students in the lab. The work will also engage high school teachers from Central New York, who will conduct 6-week summer research internships. Technical AbstractDespite the ubiquity of sheets in our everyday lives and their importance to a range of technologies, we nevertheless lack a general predictive framework for when a buckled sheet will have a smooth or sharp character. The overarching goal of the project is to measure, quantify, and predict when an elastic film will form sharp, singular features where stresses and strains spontaneously condense to a small set. The project focuses on situations where there are no applied tensile loads to organize the buckling patterns. One set of experiments will use a stamping setup where a thin sheet is confined in the gap between two curved walls. A second set of experiments will investigate the buckling of an ultrathin spherical cap confined to a liquid bath. The buckling patterns range from smooth concentric circular wrinkles, to smectic domains of parallel wrinkles separated by sharp grain boundaries. The project will characterize the transitions between these morphologies while pursuing a tantalizing link to a polygonalization transition in indented shells. This research lies at the intersections of physics, applied mathematics, and engineering, and the project engages with general themes in condensed matter including singularities, symmetry breaking, and order-disorder transitions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术抽象的材料可以弯曲，扭曲和皱纹成多种形式。所得的形状可以像花的起伏边缘一样光滑，也可以像弯曲的箔球中的折痕和点一样锋利。这项研究的目的是了解这些功能何时变得光滑，而何时尖锐。这个看似简单的问题令人惊讶地很难回答，并且会影响依赖薄纸的各种技术。该项目由一套模型实验组成，其中聚合物膜被迫将其变成不同的几何形状，从而迫使它们屈服。由于该项目的重点是应无限制的身体行为，因此我们的发现应适用于从非常小到非常大的物质系统，从石墨烯膜到食品包装再到可部署的卫星。这项研究与针对广泛受众的一系列教育和外展项目相结合。该项目将培训两名博士生，他们将与实验室中的大学生和高中生一起工作。这项工作还将吸引来自纽约中部的高中老师，他们将进行为期6周的夏季研究实习。技术摘要尽管在我们的日常生活中的床单无处不在及其对各种技术的重要性，但我们仍然缺乏一般的预测框架，因为何时屈曲的床单具有光滑或鲜明的特征。该项目的总体目标是测量，量化和预测弹性膜何时会形成鲜明，奇异的特征，在这种特征中，应力和压力自发地凝结到小型集合。该项目着重于没有施加拉伸负荷来组织屈曲模式的情况。一组实验将使用冲压设置，其中将薄纸限制在两个弯曲墙之间的缝隙中。第二组实验将研究局限于液体浴的超薄球形帽的屈曲。屈曲图案范围从光滑的同心圆形皱纹到平行皱纹的近晶域，这些皱纹被尖锐的晶界隔开。该项目将表征这些形态之间的过渡，同时追求凹痕壳中多边形过渡的诱人联系。这项研究在于物理学，应用数学和工程学的交叉点，该项目与凝结物质的一般主题相关联，包括奇异性，对称性破坏和订单命令过渡。这项奖项反映了NSF的法定任务，并通过基金会的知识优点和广泛的影响来通过评估来通过评估来进行评估。