Method for measuring internal contact pressure between mating solid parts separated by a liquid film

摘要

A method is provided for directly measuring the contact pressure on the mating interfaces of two solids (7, 8) undergoing compression where the interfacial region contains an entrapped film (squeeze film) of liquid, grease or slurry. The method comprises the following steps: 1. directing an acoustic pulse at either interface; 2. measuring a reference amplitude of the acoustic pulse reflected from the interface as it bears initial contact pressure (normally zero); 3. measuring a second "loaded" amplitude of the acoustic pulse reflected from the interface when the interface is bearing a different contact pressure; 4. computing from the reference and loaded amplitude measurements a ratio or other measure directly indicative of the change in contact pressure; and 5. relating said ratio to contact pressure through a calibration curve, developed using the above steps over a range of known contact pressures, for the specific material of the solid bodies and film under consideration. a