Abstract Model non-Newtonian fluids are used to determine the influence of fluid rheology on friction between viscoelastic substrates. We uniquely designed two groups of fluids to be iso-viscous at low- and high-shear rate respectively using nanocellulose dispersions. While high-shear viscosity defines the elastohydrodynamic (EHL) region, below this limit a secondary transition in the Stribeck curve is found to be influenced by the low-shear viscosity; this is more pronounced for rough substrates and absent for Newtonian lubricants. We consider this to indicate that viscosity at low shear rates surprisingly has a strong influence on micro-EHL as well as fluid entrainment and complex fluid-asperity interactions in the boundary-mixed regimes. A conceptual model is proposed for non-Newtonian fluids in soft-lubrication.

中文翻译：

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模型剪切稀化流体的软润滑

摘要 模型非牛顿流体用于确定流体流变学对粘弹性基底之间摩擦的影响。我们独特地设计了两组流体，分别使用纳米纤维素分散体在低剪切率和高剪切率下具有等粘性。虽然高剪切粘度定义了弹性流体力学 (EHL) 区域，但发现低于此限制的 Stribeck 曲线中的二次转变受低剪切粘度的影响；这对于粗糙的基材更为明显，而对于牛顿润滑剂则不存在。我们认为这表明低剪切速率下的粘度出人意料地对微 EHL 以及边界混合区域中的流体夹带和复杂的流体 - 粗糙相互作用具有强烈影响。针对软润滑中的非牛顿流体提出了一个概念模型。