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

University Of Alabama Tuscaloosa, Tuscaloosa AL

Investigators

Abstract

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.