Cavitation Properties of Oils Under Dynamic Stressing by Tension

We report measurements of the effective tensile strength Fc of commercial “multigrade” oils (in the SAE viscosity grades 5W-30 and 10W-40) over a range of temperatures T, which are representative of those encountered under their normal operating conditions (in the range 20°C⩽T⩽140°C). Also reported are the values of Fc that are obtained for Newtonian silicone oils over a range of shear viscosities. In the experiments reported herein, samples of liquid are subjected to dynamic stressing by a pressure-tension cycle, this being a feature of the conditions experienced by a lubricant within a dynamically loaded journal bearing and the method used to estimate Fc avoids reliance on direct measurements of substantial dynamic tensions using conventional pressure transducers.