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

为了保护建筑物免受地震振动的影响，保护残肢免受运动的影响，开发能够安全有效地消散这些力量能量的材料至关重要。磁流变液（mrf）是油中磁性颗粒的混合物，在磁场作用下形成链。MRF链不会因振动或冲击而断裂，而是以热量的形式释放能量，从而减少了对周围结构或生物材料的机械损伤。然而，典型的磁磁共振磁振器需要大量的功率来维持高磁场。这是一个挑战，因为在地震时无法获得电力，或者用于假肢的可穿戴高功率电池的安全性较差。该奖项旨在开发一种新型的基于水包油乳剂的磁阻材料，该材料可以在较低的磁场下实现更好的能量耗散，并且能耗显著降低。本文将从实验和理论两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之间的关系。该奖项的成果不仅将提高基础设施对自然灾害的抵御能力，改善截肢者的生活质量，还将支持研究生在STEM职业道路上的指导。耗散能量的材料对于各种各样的工程问题是必需的，例如承受地震振动或人体运动的影响。需要新的材料来提高假肢的抗震能力和舒适性。为了满足这一需求，磁流变液（mrf）可以用作粘性阻尼器的一部分，以安全有效地消散大量能量。磁流变因子是一种磁粒子分散体，当受到磁场作用时，会形成链状并抵抗流动。mrf的采用在很大程度上受到限制，这是由于大规模或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化的MRF配方，以减少MRF功率需求。实验和理论相结合的方法将用于实现以下目标：(1)确定控制磁流变液乳液性能的关键参数，(2)可视化磁流变液乳液的磁化状态形态，以及(3)建立一个基本框架来概括这种现象。该奖项能够改善基础设施和假肢设备，同时也为研究生提供STEM指导和经验。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.