RUI: Magneto-Mechanical Coupling in Isotropic vs. Anisotropic, Hard- vs. Soft- Magnetic Magnetorheological Elastomers

磁流变弹性体(MRE)是由橡胶(弹性体)制成的复合材料。和磁性颗粒，其力学行为(？流变学？)磁场的变化。有关磁流变弹行为的理论将这种变化归因于粒子内部产生的磁力矩。然而，这项工作解决了由不产生内部扭矩的软磁颗粒形成的MRE和由产生磁力矩的硬磁性颗粒(例如永磁体)形成的MRE之间的根本行为差异。这项工作的目的是研究不同材料成分的剪切和压缩的有效模数、磁化引起的应变(或磁致伸缩)和微观结构。有效模数将通过测量材料--S对振动的响应来确定。磁致伸缩将使用光学显微镜进行测量。并利用X射线层析成像技术对其微观结构进行了表征。最后，材料做功的能力将通过确定可以产生的力的大小来衡量。磁流变液在技术上很重要，因为预计它们在工作寿命内比最接近的竞争对手磁流变液表现得更好。这项研究很重要，因为软磁粒子和硬磁粒子之间的根本区别导致了几种可以利用的磁力对称性的定义。例如，作者发现，使用硬磁颗粒的磁流体可以作为可逆执行器，而使用软磁颗粒的磁流体不能作为可逆执行器。这项工作将通过罗文？S工程诊所和物理研究课程吸引10+名本科生。这个项目的主题将在材料科学、计算材料科学和(高级)固体力学课程中使用。参加材料科学夏季研究所、R.U.M.E./C.H.A.M.P.星期六学院和EOF/MAP预科研究所的K-12学生也将接触到这项研究。

Magnetorheological elastomers (MREs) are composite materials, made from rubber (?elastomers?) and magnetic particles, whose mechanical behavior (?rheology?) changes in a magnetic field. Theories on MRE behavior assign this change to magnetic torques developed within the particles. This work, however, addresses the fundamental difference in behavior between MREs formed from soft-magnetic particles like iron, which do not develop internal torques, and those formed with hard-magnetic particles (e.g. permanent magnets) that do generate magnetic torques. The objectives of this work are to study the effective modulii in shear and compression, magnetization induced strain (or magnetostriction), and microstructure of different material compositions. Effective modulii will be determined by measuring the material?s response to vibration. Magnetostriction will be measured using optical microscopy. And, the microstructure will be characterized using x-ray tomography. Finally, the ability of the material to perform work will be measured by determining the amount of force that can be generated.MREs are technologically important because they are expected to perform better over their working lifetimes than their closest competitors, magnetorheological fluids. This study is important because the fundamental difference between soft-magnetic and hard-magnetic particles leads to definitions of several magneto-mechanical symmetries which may be exploited. For example, the authors have found that MREs using hard-magnetic particles can serve as reversible actuators whereas MREs using soft-magnetic particles cannot. This work will engage 10+ undergraduates through Rowan?s Engineering Clinics and Physics Research courses. Topics from this project will find use in Materials Science, Computational Materials Science, and (Advanced) Solid Mechanics courses. K-12 students participating in the Summer Institute in Materials Science, R.U.M.E./C.H.A.M.P. Saturday Academy, and the EOF/MAP Precollege Institute will also be exposed to this research.