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: 0932680
• 负责人: Daniel Klingenberg
• 金额: $ 19.94万
• 依托单位: University of Wisconsin-Madison
• 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=0932680&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 societys 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.

磁流变液(0932680/0932715Klingenberg/ZauscherMagnetorheological，MR)是可磁化颗粒的悬浮液，其流变性可在外加磁场的作用下发生显著且可逆的改变。这些材料可用于各种应用，目前的注意力主要集中在汽车装置(如主动减振系统和离合器)上。应用程序可以改善车辆质量(例如，平顺性和操纵性)以及提高车辆的燃油里程。过去的研究表明，磁流变液的场致行为在很大程度上可以用静磁力及其与流体动力力的竞争来解释。然而，磁流变液的应用需要其他特性的某些与设备相关的特性，如关闭状态粘度、沉降性、再分散性和耐久性。这些性质受到磁力以外的粒间力的强烈影响。因此，很明显，设计用于设备的磁流变液需要了解各种颗粒间力和悬浮液宏观性质之间的关系。在拟议的工作中，我们将使用几种互补的方法来探索粒子间力和宏观行为之间的关系，并研究观察到的行为的机制。通过将各种物种嫁接到铁表面上，铁表面之间的非磁力将会改变。接枝层对颗粒间作用力的影响将使用胶体探针显微镜直接确定，在该显微镜中将测量法向和横向(即摩擦)。还将通过实验确定接枝层对宏观流变性的影响。最后，我们将使用粒子级别的模拟来检查粒子间作用力的变化如何影响宏观行为。这将使我们能够确定观察到的由表面上的接枝物种引起的颗粒间作用力的变化是否可以解释观察到的宏观性质的变化。拟议的研究将提供有关磁流变液性能的新信息，并提高我们优化流体和各种应用所需的颗粒涂层的能力。这项工作还将更全面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人的井深的系统，具有更大颗粒的系统，并探测比通常研究的更大变形的流变性。该项目的资金将用于支持研究生，他们将接受磁流变学新兴领域的培训，以及胶体探针显微镜和更一般的胶体凝胶和悬浮流变学领域的培训。学生们还将通过与通用汽车的互动，接触到他们的工作在工业上的应用。我们的团队每年也会让本科生参与研究，因此我们还将在整个项目过程中培训一批本科生在MR、悬浮流变学和胶体科学方面的知识。私人投资促进机构还参与了其他将从拟议工作中受益的教育项目。克林根贝格教授一年级的课程《社会概论》是工程学的重大挑战，该课程研究了社会如何面临重大挑战将需要工程师来解决这些挑战。这门课程的目标是招收工程专业的新学生，并招聘和留住更大比例的女性。社会面临的主要挑战之一是能源可持续性。MR技术的大量应用受到汽车节能的推动，因此被纳入大挑战课程，以说明当前的研究活动是如何应对社会？S的挑战。在过去的6年里，佐斯彻一直参与了REU的一个项目，该项目为加拉德特大学的听力障碍学生提供实验室体验。我们建议每年夏天聘请一名这样的学生参加CPM测量。