剪切增稠液及阻尼器性能研究

Performance of shear thickening fluid and a damper as its application

以聚苯乙烯-丙烯酸乙酯纳米粒子为分散介质,制备剪切增稠液(Shear Thickening Fluid,STF),研究以STF为工作介质的双出杆式阻尼器动态性能,利用流变仪测量STF流变特性。实验结果显示,STF粘度特性曲线呈现明显非线性:低剪切速率时轻微剪切变稀(shear thinning);达临界剪切速率后剪切增稠(shear thickening)。利用MTS对阻尼器进行不同频率、不同振幅加载条件下的动态测试,结果表明,阻尼器工作在STF剪切增稠区间时,STF粘度急剧增加,储能模量、耗能模量迅速增大,阻尼器输出力跃升,表现出巨大的吸收及耗能能力。采用以有效刚度、有效粘滞阻尼建立线性模型,定性评价STF阻尼器的弹性特性、阻尼特性。

A shear thickening fluid （STF） composed of polystyrene-ethyl acrylate （PST-EA） nanoparticles suspended in glycol was prepared and the dynamic properties of a damper as its application were investigated. The rheologieal properties of STF were measured including with a rheometer. Test results showed that the viscosity curves of STF can be divided into two regions including slight shear thinning at lower shear rate, significant shear thickening at critical shear rate and dynamic tests of a STF-filled damper were conducted by using a material test system （MTS） with varying excitation frequency and load amplitude. When the damper was subjected to external applied excitation at critical shear rate, the output force abruptly increases due to a steep rise in viscosity of STF, and a rise of energy-storage modulus and energy-loss modulus. It was indicated that STF has tremendous ability of energy-absorption and energy-dissipation. A linear model with effective stiffness and effective viscous damping was developed in order to evaluate qualitatively the elastic and damping characteristics of a STF-filled damper.