A System for Measuring Lubrication Film in Reciprocating Oscillating Bionic Artificial Joint

A measuring system of reciprocating biomimetic artificial joint lubrication film was introduced. Firstly, a friction pair composed of ceramic ball-polydimethylsiloxane (hereinafter referred to as PDMS) soft layer-glass disk was constructed to simulate bionic artificial joint structure consisting of femoral head, articular cartilage and socket respectively. Secondly, the loading actuator, motion actuator and ambient temperature of point contact oil film measuring device awere redesigned and improved, which could better simulate the bearing load, motion mode and ambient temperature in actual the joint motion. Finally, three measurement examples of lubrication film formed in bionic artificial joints were presented. The measurement results demonstrated that larger deformation of PDMS soft layer with low elastic modulus could capture more lubricating fluid to flow into the contact area under the same bearing load, which was attributed to the formation of an effective lubricating., when the fixed load and impact load were applied on ceramic ball lubricated by silicone oil and water lubrication, the deformation of PDMS soft layer was measured visually with time. It was found that the deformation changed quickly in the initial very short time when the load was applied, and then became slow gradually. The lubricating film formed in the whole process of reciprocating swing of ceramic ball applied by fixed load was observed in situ, and the deformation of soft layer was measured synchronously. This measurement system provided a new technical means for evaluating the lubrication properties of bionic lubricating materials, and was of great significance to reveal the lubrication mechanism of bionic artificial joints.