Thesis
Effect of gap size on magnetorheological device design
Washington State University
Master of Science (MS), Washington State University
05/2020
DOI:
https://doi.org/10.7273/000004087
Handle:
https://hdl.handle.net/2376/125021
Abstract
This research aims to reduce the discrepancies between simulation and experimental torque outputs in magnetorheological brake devices. A key material property used in these simulations is the relationship between yield stress and the magnet field strength. Commercial magnetorheological fluids often have this relationship measured with a fluid gap size of 0.039", yet may be used in gaps smaller than 0.0025". To investigate if the gap size is effecting this relationship a custom rheometer was designed and manufactured with an adjustable gap size. The first experiment was run with a 0.039" gap and validated the published results. The second experiment was run with a 0.010" gap and found that the yield stress of the fluid increased compared 0.039" gap. The third experiment was run with a 0.0025" gap and found that the yield stress of the fluid was lower than both other gap sizes. The results from the 0.010" gap were used to simulate the torque output of a magnetorheological drum brake with the same gap size. The max error from the simulations dropped from 20% using the 0.039" gap data to 6% using the 0.010" gap data. The results from the 0.0025" gap were used to simulate the torque output of a magnetorheological disk brake with the same gap size. The max error from the simulations increased from 38% using the 0.039" gap data to 65% using the 0.0025" gap data. This research shows that torque simulations can be improved by using data collected at a similar sized gap. When the gap gets extremely small, ≈ 0.0025", this doesn't hold as other factors like particle separation or aggregation may be causing significant effects. Using this research, magnetorheological devices can be better optimized by using the yield stress relationships measured at the device gap. With more research, particle aggregation or separation may be controlled and allow these magnetorheological brakes a larger dynamic range of torques.
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Details
- Title
- Effect of gap size on magnetorheological device design
- Creators
- Jason N. Cowin
- Contributors
- HAKAN BERAT GUROCAK (Advisor) - Washington State University, School of Engineering and Computer Science (VANC)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Engineering and Computer Science (VANC)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900890787901842
- Language
- English
- Resource Type
- Thesis