弹塑性流变模型在弹流脂润滑特性分析中的应用

采用自行研制的高速润滑脂拖动力试验装置测量了7007国产润滑脂的拖动力;以7007润滑脂为例,建立了该类高速润滑脂的平均剪切弹性模量和平均极限剪切应力的计算公式,基于Tevaarwerk-Johnson弹塑模型给出了拖动力的计算方法,并分析了其流变特性.结果表明:该润滑脂在本文试验条件下表现出弹塑性,其拖动力的理论预测值与试验测量值具有很好的一致性;所建立的拖动力计算公式可用于指导润滑分析领域的工程计算.

Application of Elastic/Plastic Rheological Model in Characteristics Analysis of Elastohydrodynamic Lubrication of Grease

A modified ball-on-disc test rig was performed to measure the traction forces of a bi-ester type domestic lithium grease No.7007. Two equations for calculating the average limiting shear stress and shear elastic modulus of the grease in elestohydrodynamic (EHD) lubrication condition were derivated. The method to calculate the traction forces of the grease was presented based on the elastic/plastic rheological model introduced by Johnson and Tevaarwerk. One example calculation was then made for grease No.7007 and its rheological properties were analyzed. The results showed that the lithium grease behaved elastic and plastic throughout the experimental conditions and the calculated traction force agreed well with the measured one. The semi-empirical equations for calculating the traction force of the grease in EHD condition could be used to guide the lubrication analysis in engineering computing.