EAPSI:EAPSI: Investigation of the Wrinkling and Buckling Behavior of Layered Soft Materials with Applications in the Developing Brain

EAPSI：EAPSI：研究层状软材料的起皱和屈曲行为及其在发育中大脑中的应用

• 批准号: 1515340
• 负责人: Maria Holland
• 金额: $ 0.01万
• 依托单位: Holland Maria
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1515340&HistoricalAwards=false
• 关键词: EAPSI; Investigation; Wrinkling; Buckling; Behavior

During the third trimester of gestation, the human brain evolves from having a mostly smooth surface to the characteristic 'wrinkled' appearance of the adult brain. How does this happen, and why does it sometimes go wrong? The mechanics community has been interested in these questions for decades, attempting to model the brain as a thin, stiff, growing layer (gray matter) attached to a thicker, softer layer (white matter). Recent mechanical tests, however, have revealed that gray matter is actually slightly less stiff than the underlying white matter, challenging many prior models and assumptions. Through collaboration with Dr. Feng Xi-Qiao of Tsinghua University in Beijing, China, an expert in the wrinkling and buckling of soft films, this project will explore the behavior of thin growing layers on substrates of a similar stiffness. This research will lead to a greater understanding of brain development in light of these recent findings.For a stiff growing layer on a soft substrate, the formation of sinusoidal waves is expected, while the growth of a soft layer on a stiffer substrate will lead to creases with pinched valleys. The transition between waves and creases happens gradually in the region of interest for brain tissue. Using both analytical and numerical approaches, this research will explore the behavior of soft layered materials with stiffness ratios close to unity. Numerical simulations will be performed in the finite element software Abaqus, using the built-in linear perturbation analysis as well as user-defined material models that simulate volumetric growth. This NSF EAPSI award is funded in collaboration with the Chinese Ministry of Science and Technology.

在妊娠晚期，人类大脑从大部分光滑的表面演变为成人大脑特有的“皱纹”外观。 这是如何发生的，为什么有时会出错？ 几十年来，力学界一直对这些问题感兴趣，试图将大脑建模为一个薄而僵硬的生长层（灰质），附着在一个更厚、更软的层（白质）上。 然而，最近的机械测试表明，灰质实际上比下面的白质硬度稍低，这对许多先前的模型和假设提出了挑战。 通过与中国北京清华大学的软膜起皱和屈曲专家冯锡桥博士合作，该项目将探索类似刚度基材上薄生长层的行为。 根据这些最新发现，这项研究将有助于人们更好地了解大脑发育。对于柔软基质上的坚硬生长层，预计会形成正弦波，而较坚硬基质上的柔软层生长将导致出现收缩谷的折痕。 波浪和折痕之间的过渡在脑组织感兴趣的区域逐渐发生。 本研究将采用分析和数值方法，探索刚度比接近一致的软层状材料的行为。 数值模拟将在有限元软件 Abaqus 中进行，使用内置的线性扰动分析以及用户定义的模拟体积增长的材料模型。该 NSF EAPSI 奖项由与中国科学技术部合作资助。