摘要：在不同的磁场强度H、剪切速率γ和温度T下,测试了纳米复合磁流变(MR)液的磁致剪切应力△τ以及响应时间△_tο结果表明,H、γ和T对纳米复合MR液的△t的影响较小,纳米复合MR液对撤消磁场的响应比施加磁场的响应略慢;随H增加,△_τ增加;随户提高、△τ出现最大值;随T升高,△τ缓慢降低。它们之间的定量关系可用公式△τ=kHH+(Kγ1-kγ2γ)γ-kt△T来描述,其中:kH=28.32,kγ1=2.85,kγ2=0.0013,kt=3.8。用它能较全面地评价纳米复合MR液的性能,并可作为设计磁流变液智能器件的基础。

关键词：磁流变液;磁致剪切应力;响应时间;羰基铁;铁纳米粒子;纳米复合

Abstract: The magnetic field-induced shear stress( A r )and the responsetime ( At) for a nanocomposite-based magnetorheological(MR) suspensionwere determined as functions of magnetic field strength (H ), shear rate (yand temperature (T). The results showed that At had almost independenceof H,Y and T.The MR suspension responded to external magnetic field alittle lower at “switching off” than at “switching on” .A increased withthe increase of H, a maximum of A t occurred with increasing Y,and A Tslowly decreased with T. The quantity relationship among them fitted inwith the equation of A r=kH+(k k) y -kA T very well, wherek=28.32,k=2.85,k,=0.0013,k=3.8.Using this equation can charac-terize well the properties for the MR suspensions,which is the basis ofdesigning MR intelligent devices.

Keywords: magnetorheological fluid; shear stress; pesponse time; car-bonyl iron; iron nanoparticles; nanocomposite