Generating a Stribeck curve in a reciprocating test (HFRR/SRV-type test)

This application note from Bruker discusses the Stribeck curve, which represents the frictional characteristics of a liquid lubricant under different conditions. The curve is divided into boundary, mixed, and hydrodynamic regimes based on film thickness to surface roughness ratio. Traditional tests used a journal-bearing geometry, but there is interest in using reciprocating test modes like the high-frequency reciprocating rig (HFRR) to evaluate lubricant friction. The note describes a test setup using a polished cylindrical dowel pin and a flat plate with a Bruker universal mechanical tester (UMT)-3 instrument. Reciprocating tests allow for evaluating lubricants in real-world scenarios. The conclusion highlights the capabilities of Bruker's UMTs for generating Stribeck curves in reciprocating tests, relevant for lubricant development in various engineering applications.