Assembly Mechanism Investigation and Theoretical Framework Development of Magnetorheological Emulsions for Low Power Energy Dampers

为了保护建筑物不受地震震动的影响，保护残肢不受运动的影响，关键是开发能够安全有效地分散这些力的能量的材料。磁流变液(MRF)是在磁场作用下形成链的磁性颗粒在油中的混合物。磁流变液链条不会因振动或冲击而断裂，而是以热量的形式释放出来，减少对周围结构或生物材料的机械损害。然而，典型的磁流变场需要大量的功率来维持高磁场。这是一个挑战，因为地震期间无法获得电力，或者用于假肢的可穿戴式高功率电池安全性较差。该奖项旨在开发一种基于水包油乳状液的新型磁流变液，可以在较低的磁场下实现更好的能量消耗，使用显著更少的功率。将从实验和理论两个方面探讨磁流变液配方中的关键因素以及磁流变液链结构与整体性能的关系。这一奖项的结果不仅将提高基础设施对自然灾害的复原力，还将改善截肢者的生活质量，还将支持研究生在通往STEM职业生涯的道路上提供指导。对于各种各样的工程问题来说，耗散能量的材料是必不可少的，例如承受地震振动或人类运动的影响。需要新材料来提高地震恢复力和假肢舒适性。为了满足这一需求，磁流变液(MRF)可以作为粘滞阻尼器的一部分，以安全有效地耗散大量能量。磁流变液是一种磁性粒子分散体，当受到磁场作用时，会形成链条并阻止流动。MRF的采用在很大程度上受到了限制，这在很大程度上是因为对大规模或身体上应用的不可接受的功率要求。该奖项研究了一种新的基于乳剂的磁流变液配方，以降低磁流变液的功率要求。将使用实验和理论相结合的方法，目的是(1)确定控制磁流变液乳剂性能的关键参数，(2)可视化磁化状态的磁流变液乳剂的形态，以及(3)开发一个基本的框架来概括这些现象。该奖项在改善基础设施和假体设备的同时，还为研究生提供STEM指导和经验。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

To protect buildings from earthquake vibrations and residual limbs from the impact of movement, it is critical to develop materials that can dissipate the energy of these forces safely and effectively. Magnetorheological fluids (MRFs) are mixtures of magnetic particles in oil that form chains under a magnetic field. MRF chains resist being broken up due to vibration or impact, instead releasing that energy as heat, reducing the mechanical damage to surrounding structural or biological material. Typical MRFs, however, require large amounts of power to maintain a high magnetic field. This is a challenge due to inaccessible power during an earthquake or poor safety of wearable high-power batteries for prosthetics. This award seeks to develop a new type of MRF based on oil-in-water emulsions that can achieve better energy dissipation at lower magnetic fields, using significantly less power. The critical factors in MRF formulation will be explored as well as the relationship between MRF chain structure and overall performance both experimentally and theoretically. The results of this award will not only improve infrastructure resiliency to natural disasters as well as improve the quality of life of amputees but will also support the mentorship of graduate students along their path towards STEM careers. Materials which dissipate energy are necessary for a wide variety of engineering problems, such as to withstand seismic vibrations or the impact of human motion. New materials are needed to improve earthquake resiliency and prosthetic limb comfort. To address this need, magnetorheological fluids (MRFs) can be used as part of viscous dampers to dissipate large amounts of energy safely and effectively. MRFs are magnetic particle dispersions that, when subjected to a magnetic field, form chains and resist flow. The adoption of MRFs has been limited in large part due to unacceptable power requirements for large-scale or on-body applications. This award investigates a new emulsion-based formulation for MRFs to reduce the MRF power requirement. A combined experimental and theoretical approach will be used with the objectives of (1) determining the key parameters that govern the performance of MRF-emulsions, (2) visualizing the magnetized state MRF-emulsion morphology, and (3) developing a fundamental framework to generalize the phenomena. This award enables the improvement of infrastructure as well as prosthetic devices while also providing STEM mentorship and experience for graduate students.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.