Professor Masami NAKANO
Magneto-Rheological (MR) Fluids and The Advanced Technologies
Magneto-Rheological(MR) fluids are the suspensions with micron-sized ferromagnetic particles dispersed into carrier oil, and behave like a Bingham fluid having yield stress which can be rapidly changed in a reversible manner by applying magnetic field.
In this talk, two types of newly developed MR fluids will be introduced. One is ” bidisperse MR fluids” consisting of micro (6.6 um) and nano (110 nm) iron particles dispersed into silicone oil. The MR effects of the bidisperse MR fluids change significantly as a function of the solid fraction of nano-particles. Interestingly, the field-induced shear stress is significantly enhanced when the solid fraction of nano-particles is 25%. The enhancement of the MR effects can be attributed to the static formation of distinct and wide particle cluster chains reinforced with nano-particles, and the breaking and reconnection of many thicker particle columns in the shear flow mode. The other is “dry MR fluids without liquid medium”, featuring extremely low zero-field viscosity and higher operating temperature. The dry MR fluid is a novel MR fluidic powder, which is mainly composed of micron-sized carbonyl iron particles coated with nano-sized particles without liquid medium. The amount ratio of the nano-sized particles to the micron-sized carbonyl iron particles is optimized from both viewpoints of the fluidity and MR effects of the dry MR fluids.
As novel seismic MR dampers, two types of seismic MR dampers will be introduced. The first one is a newly developed “passive type MR damper” using two permanent magnets, MR valves and check valves, which has variable damping characteristics as well as an existing semi-active damper, although it is fully passive device without any sensor, power supply and controller. The second one is a seismic “linear motion MR damper utilizing MR fluid porous composite” made of porous materials impregnated with MR fluid, which mainly consists of a ball screw and a rotary MR brake. The rotary MR brake has multi-disks between which the sheets of MR fluid porous composites are installed, and an electromagnet.
As novel MR brakes, two types of MR brakes for compact electric vehicles (EV) will be introduced. The first one is a multi-layered disk type MR fluid brake for use as four wheel brakes of a super-compact electric vehicle. The four developed MR brakes have been installed into four wheels of the electric vehicle, and the running tests have been conducted. The second one is a novel dry MR fluid brake of single disk type utilizing the optimized dry MR fluids. The zero-field drag torque and the field-induced torque have been investigated as a function of the rotational speed and the applied current or magnetic field.
Masami Nakano received his Ph.D. in Mechanical Engineering from Waseda University (Tokyo, Japan) in 1982. Currently, he is a Professor and Director of Intelligent Fluid Control Systems Laboratory at the Institute of Fluid Science in Tohoku University, Japan. Before joining the Institute of Fluid Science in 2008, he was a Professor at Department of Mechanical Systems Engineering in Yamagata University, Japan. Prof. Nakano has the last 28 year’s experiences of researching and developing ER and MR materials and the associated technologies. His current research interests are the fabrication and characterization of new ER/MR fluids & soft composite materials, the smart applications of ER/MR fluids & soft composite materials to mechanical and structural vibration control systems, MEMS, rehabilitation machine systems, energy absorbing systems, vehicles, and so on. He is a Fellow of the JSME, a Director of the Japan Fluid Power Systems Society (JFPS) and a Chairman of JFPS Research Committee on “Next-generation Fluid Power Systems utilizing Functional Fluids”, and has received the Best Paper Awards (1981, 2007), the Fluid Engineering Division (FED) Award (2010), Frontier Award of FED (2003) and the Technology and Research Award (2003, 2007) from the JSME, the Excellent Paper Award (2010) from the Fluid Power Technology Promotion Foundation, the Best Paper Awards (2015) from JSAE (Society of Automotive Engineers of Japan), the Tsuchiya Kazuo’s Paper Award (2016) from JSPO(the Japanese Society of Prosthetics and Orthotics), and Academic Contribution Award (2017) from JFPS (the Japan Fluid Power Systems Society), etc.
After the presentation, you are welcome to join the finger lunch with Dr Rennie for further research discussion in BLD 8.G24 from 12:00-13:00.
Photos from the seminar: