GOALI Collaborative Research: Engineering magnetorheological fluids by controlling nonmagnetic particle interactions

GOALI 合作研究：通过控制非磁性粒子相互作用来设计磁流变流体

• 批准号: 0932715
• 负责人: Stefan Zauscher
• 金额: $ 20.01万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0932715&HistoricalAwards=false
• 关键词: GOALI; Collaborative; Research; Engineering; magnetorheological

0932680/0932715Klingenberg/ZauscherMagnetorheological (MR) fluids are suspensions of magnetizable particles, whose rheological properties can be dramatically and reversibly altered by applied magnetic fields. These materials can be exploited in a variety of applications, with much of the current attention focused on automotive devices (e.g., active damping systems and clutches). Applications can improve vehicle quality (e.g., ride and handling) as well as improve the gas mileage of vehicles. Past research has illustrated that the field induced behavior of MR fluids can be explained largely in terms of magnetostatic forces and their competition with hydrodynamic forces. However, applications of MR fluids demand certain device dependent characteristics of other properties, such as off state viscosity, sedimentation, redispersability, and durability. These properties are strongly influenced by interparticle forces other than magnetic forces. It is thus apparent that designing MR fluids for devices requires an understanding of the relationships between various interparticle forces and macroscopic properties of the suspensions. In the proposed work, we will use several complementary approaches to probe the relationships between interparticle forces and macroscopic behavior, and to investigate the mechanisms for observed behavior. Nonmagnetic forces between iron surfaces will be altered by grafting various species to the surfaces. The impact of the grafted layers on interparticle forces will be determined directly using colloidal probe microscopy, in which both the normal and lateral (i.e., friction) will be measured. The effects of the grafted layers on the macroscopic rheological properties will also be determined experimentally. Finally, we will use particle level simulations to examine how changes in interparticle forces affect macroscopic behavior. This will allow us to determine if changes observed in the measured interparticle forces caused by grafting species on the surfaces can account for the observed changes in macroscopic properties.Intellectual merit. The proposed research will provide new information about the properties of MR fluids, and improve our ability to optimize fluids and requisite particle coatings for various applications. This work will also more generally improve our understanding of particulate gels, as we will be investigating systems with deeper attractive well depths, systems with larger particles, and probing larger deformation rheological properties than typically studied.Broader impact. Funding for this project will be used to support graduate students, who will be trained in the emerging field of magnetorheology, as well as colloidal probe microscopy and the more general fields of colloidal gels and suspension rheology. The students will also be exposed to industrial applications of their work through interactions with General Motors. Our groups also involve undergraduate students in research every year, and thus we will also be training a stream of undergraduates in aspects of MR, suspension rheology, and colloid science throughout the course of this project. The PIs are involved in other education projects that will benefit from the proposed work. Klingenberg co teaches the freshman course "Introduction to Society" is Engineering Grand Challenges, which examines how society is significant challenges will require engineers to solve them. The goals of this course are to recruit new students into engineering, and to recruit and retain a larger fraction of women. One of society's main challenges is energy sustainability. Numerous applications of MR technology are motivated by energy economy in vehicles, and thus are incorporated into the Grand Challenges course to illustrate how current research activities are addressing society's challenges. Zauscher has been involved over the last 6 years in an REU program that provides laboratory experiences for hearing impaired students from Gallaudet University. We propose to engage one such student each summer in the CPM measurements.

0932680/0932715Klingenberg/Zauscher 磁流变 (MR) 流体是可磁化颗粒的悬浮液，其流变特性可通过施加的磁场发生显着且可逆的改变。这些材料可用于多种应用，目前的大部分注意力集中在汽车设备（例如主动阻尼系统和离合器）上。应用程序可以提高车辆质量（例如行驶和操控）以及提高车辆的油耗。过去的研究表明，磁流变流体的场感应行为很大程度上可以用静磁力及其与流体动力的竞争来解释。然而，MR 流体的应用需要某些与设备相关的其他特性，例如离态粘度、沉降性、再分散性和耐久性。这些特性受到磁力以外的颗粒间力的强烈影响。因此，显然，为设备设计 MR 流体需要了解各种颗粒间力与悬浮液宏观特性之间的关系。 在拟议的工作中，我们将使用几种互补的方法来探讨粒子间力与宏观行为之间的关系，并研究观察到的行为的机制。 通过将各种物质接枝到表面，可以改变铁表面之间的非磁性力。接枝层对颗粒间力的影响将使用胶体探针显微镜直接确定，其中法向力和横向力（即摩擦力）都将被测量。接枝层对宏观流变性能的影响也将通过实验确定。最后，我们将使用粒子级模拟来检查粒子间力的变化如何影响宏观行为。 这将使我们能够确定在由表面接枝物质引起的测量到的颗粒间力中观察到的变化是否可以解释观察到的宏观性能的变化。智力价值。拟议的研究将提供有关磁流变流体特性的新信息，并提高我们为各种应用优化流体和必要颗粒涂层的能力。这项工作还将更广泛地提高我们对颗粒凝胶的理解，因为我们将研究具有更深吸引力井深的系统、具有较大颗粒的系统，并探测比通常研究更大的变形流变特性。影响更广泛。该项目的资金将用于支持研究生，他们将接受磁流变学、胶体探针显微镜以及胶体凝胶和悬浮流变学等更普遍领域的培训。学生还将通过与通用汽车公司的互动来接触其工作的工业应用。我们的课题组每年也会让本科生参与研究，因此我们也会在整个项目过程中对一批本科生进行MR、悬浮流变学和胶体科学方面的培训。 PI 参与的其他教育项目将从拟议的工作中受益。克林根伯格教授的新生课程“社会概论”是工程重大挑战，该课程探讨了社会如何成为需要工程师解决的重大挑战。本课程的目标是招收工程学新生，并招收和留住更多女性。社会面临的主要挑战之一是能源可持续性。 MR 技术的众多应用都是受到车辆能源经济的推动，因此被纳入“重大挑战”课程中，以说明当前的研究活动如何应对社会挑战。 Zauscher 在过去 6 年里一直参与 REU 项目，该项目为加劳德大学听障学生提供实验室体验。 我们建议每年夏天让一名这样的学生参与 CPM 测量。