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.

非技术摘要薄材料可以弯曲、扭曲和起皱，形成多种形式。由此产生的形状可以像花朵的起伏边缘一样光滑，也可以像皱巴巴的箔球中的折痕和点一样尖锐。这项研究的目的是了解这些特征何时变得平滑，何时变得尖锐。这个看似简单的问题实际上很难回答，并且它影响了各种依赖薄片的技术。该项目由一系列模型实验组成，其中聚合物薄膜被强制形成不同的几何形状，迫使它们弯曲。由于该项目关注的是无标度的物理行为，因此我们的发现应该适用于从非常小到非常大的材料系统，从石墨烯薄膜到食品包装再到可部署卫星。该研究与一系列针对广泛受众的教育和推广项目相结合。该项目将培训两名博士生，他们将在实验室与本科生和高中生一起工作。这项工作还将聘请来自纽约中部的高中教师，他们将进行为期 6 周的暑期研究实习。技术摘要尽管板材在我们的日常生活中无处不在，并且对一系列技术很重要，但我们仍然缺乏一个通用的预测框架来判断弯曲的板材何时具有光滑或锋利的特性。该项目的总体目标是测量、量化和预测弹性薄膜何时会形成尖锐、奇异的特征，其中应力和应变会自发地凝结成一小部分。该项目重点研究没有施加拉伸载荷来组织屈曲模式的情况。一组实验将使用冲压装置，其中将薄板限制在两个弯曲壁之间的间隙中。第二组实验将研究限制在液体浴中的超薄球冠的屈曲。屈曲图案的范围从平滑的同心圆皱纹到由尖锐晶界分隔的平行皱纹的近晶域。该项目将描述这些形态之间的转变，同时寻求与锯齿状壳的多边形化转变的诱人联系。这项研究位于物理学、应用数学和工程学的交叉点，该项目涉及凝聚态物质的一般主题，包括奇点、对称性破缺和有序-无序转变。该奖项反映了 NSF 的法定使命，并被认为值得支持通过使用基金会的智力优点和更广泛的影响审查标准进行评估。