Investigation of the relationship among the microstructure, rheological properties of MR grease and the speed reduction performance of a rotary micro-brake

Jun Dai*, Hui Chang, Rui Zhao, Jue Huang, Kaiquan Li, Saipeng Xie

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)

Abstract

A magnetorheological (MR) grease-based micro-brake is proposed for providing a damping torque for a miniature turbine generator when working at high wind speeds. MR greases with a magnetic particle volume fraction from 10% to 90% are prepared for the MR grease-based micro-brake. Flow curves show that the shear thinning behaviour of MR grease is enhanced by the increased volume fraction. The zero magnetic rheological behaviour of MR grease is studied with a Herschel-Bulkley model. Then, the speed reduction effect of the MR grease-based micro-brake is experimentally studied. A rotational speed difference Δn as high as 6750 r/min is achieved by applying a current of 1.01 A to the micro-brake. MR grease with lower volume fraction demonstrates a more significant speed reduction effect under low applied currents, since the chain forming behaviour is enhanced by the decreased volume fraction. Finally, a comprehensive model for the MR grease-based micro-brake is developed to reveal the relationship among the microstructure, rheological properties of the MR grease and the speed reduction performance of the MR grease-based micro-brake.

Original languageEnglish
Pages (from-to)741-750
Number of pages10
JournalMechanical Systems and Signal Processing
Volume116
DOIs
Publication statusPublished - 1 Feb 2019

Keywords

  • Magnetorheological brake
  • Magnetorheological material
  • Miniature turbine generator
  • Rheological property
  • Speed reduction performance

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Dai, J., Chang, H., Zhao, R., Huang, J., Li, K., & Xie, S. (2019). Investigation of the relationship among the microstructure, rheological properties of MR grease and the speed reduction performance of a rotary micro-brake. Mechanical Systems and Signal Processing, 116, 741-750. https://doi.org/10.1016/j.ymssp.2018.07.004