纳米铁钴磁流变液的流变特性研究

Study on the Rheological Characteristics of the Iron-cobalt Nanoparticles-based Magnetorheological Suspension

在不同磁场强度 H、剪切速率 γ· 和温度 T下 ,测试了纳米铁钴磁流变 ( MR)液的磁致剪切应力 Δτ以及响应时间 t。结果表明 :H、γ· 和 T对 MR液的响应时间 t的影响很小 ,响应时间约 5 0 m s;Δτ随 H和γ· 提高而增加 ,随温度升高而缓慢降低。它们之间的定量关系可用经验公式表示 :Δτ=k HH+ ( kγ· 1 - kγ· 2 γ· ) γ· - ktΔT,其中 ,k H=13.7,kγ· 1 =2 .2 ,kγ·2 =0 .0 0 11,kt=( 0 .0 2 H - 0 .0 1)。用这些参数可较全面地评价 MR液性能并作为

The magnetic field induced shear stress (Δ τ ) and the response time (Δ t ) for a iron cobalt nanoparticles based magnetorheological (MR) suspension were determined as functions of magnetic field strength ( H ), shear rate ( γ· ) and temperature ( T ). The results showed: (1) The effects of H?γ ·and T on the response time are very little and the response times equal about 50 ms. (2) The shear stress Δ τ increases with the magnetic field strength H , and slowly decreases with temperature T . (3) The quantity relationship among them fitted in with the equation of Δ τ = k HH +(k γ·1 -k γ·2 γ·)γ·-k t Δ T very well, where k H =13.7, k γ ·1 =2.2, k γ ·1 =0.001 1, k t =(0.02 H -0.17). Using this equation can characterize well the properties for the MR suspensions, which is the basis of designing MR intelligent devices.