Real-time data-driven prediction of lubricant film thickness in line contacts

Purpose This study aims to develop a procedure to predict the lubricant film thickness of line contacts in real time. It is based on a model by Hamrock and Dowson (H&D), which has long been used to estimate the film thickness to a reasonable degree of accuracy. Design/methodology/approach In this work, the basic form of the H&D model is retained, and the model parameters are recalculated based on real-time data collected at the system level, such as load and speed. The procedure requires that the lubricant in use be put to test in a test rig equipped with a sensor based on ultrasound reflectometry. Findings The procedure allows the adaptation of the H&D model to a wide range of operating conditions and types of lubricants for improved accuracy in prediction. In particular, it is shown that the procedure is capable of capturing the effect of ageing of two commercially available greases on their film thickness. Applying the proposed method in real time enables the development of digital twins of the associated machines. Originality/value The sensor data is used to characterize a given lubricant by determining its specific H&D parameters, which can then be used to predict film thickness in machinery where that lubricant is in use.