采用自制的不同粒径的SiO2粉体，利用球磨分散技术配制具有剪切增稠特性的SiO2／PEG200悬浮液流体（STF），并利用静态浸渍方法制备STF／Kevlar复合材料，研究了粉体粒径对流体体系流变性能和复合材料防刺性能的影响。结果表明，不同粒径SiO2粉体配制的悬浮液均具有明显的剪切增稠性能，当Si2粉体质量分数相同时，流体体系的起始黏度、临界剪切速率、最大黏度均随着粒径的增大而减小。16层STF／Kevlar试样能承受24．0J锥体冲击，远远优于相同面密度的纯Kevlar试样，随着粒径的增加，试样的防锥刺性能提高。刀体冲击能量为13．0J时，STF／Kevlar试样的防刀刺性能优于相同面密度的纯Kevlar试样，随着粒径的增大，试样的被刺穿深度减小，主要表现为剪切断裂破坏。%A colloidal shear thickening fluid （STF） was generated by dispersing self-made SiO2 particles with different size in 200 molecular weight polyethylene glycol（PEG200） using the ball-milling technique. The STF/ Kevlar composites were prepared by the static impregnation method. The effect of particle size on the rheological behavior of the fluid systems and the stab resistant properties of STF/Kevlar composites were studied. The results show that the suspensions with different SiO2 particle sizes all have notable shear thickening behavior. Under the condition of the same SiO2 mass fraction, the initial viscosity, critical shear rate and highest viscosity of fluid system decrease as the particle size increasing. 16-layer STF/Kevlar targets provide protection without penetration against spike at the impacted energy of 24.0 J, which are significantly better than that of the pure Kevlar with equal areal density. As the particle size increases, the composite targets have better stab resistance against spike. Under the impacted energy of 13.0 J, the STF/Kevlar targets exhibit better stab resistance against knife than that of the pure Kevlar target with equal areal density. As the particle size increases, the depth of penetration into the backing material decreases. Shear fracture is the main damage form of the targets.
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