Session: PTG-06-01: Lubrication and Efficiency

Paper Number: 143520

143520 - An Experimental Investigation on the Effect Operating Procedure Has on Tribometer Measurements 

Tribological investigations are typically conducted on measurement devices coined tribometers. This simple measurement device can be used to measure several distinct characteristics including friction, wear, heat induced failure modes, etc. The major benefit of using a tribometer is to simulate all the characteristics of a complicated contact mechanics problem with simple machine elements. Related to power transmission, tribometers are often used to produce heuristic traction curves covering operating conditions seen in real world applications of gears and bearings. This study provides insight into the effect operating procedure has on the results of traction (friction) tests using a twin-disk tribometer.

Two sets of traction disks of different surface roughness quality are tested for their frictional performance behavior because of operating procedure. One set of disks paired two super-finished specimens against each other, simulating gear contacts seen in the aerospace industry. The second set of disks was a combination of a super-finished and as-ground disk, more representative of contact conditions seen in automotive transmissions. Measured deviations based on operating procedure clearly show an impact on frictional performance. For smoother surfaces, undesirable losses contribute more significantly to measured friction. Rough surfaces generate more heat and take much longer to reach steady-state. Unrealistic friction measurements are derived if the test duration is not long enough. In either case, improper execution of traction tests will certainly alter the accuracy of the measurements.

Since the tribometer measurements are used to develop regressed friction formulae or to directly compare elasto-hydrodynamic (EHL) model predictions, it is crucial that operating procedure does not influence measured results.

Presenting Author: Anthony Ngo The Ohio State University

Presenting Author Biography: Anthony is a Graduate Research Associate in the Gear and Power Transmission Research Laboratory. His research focuses on experimental twin-disk tribometer measurements and techniques. A focus is on frictional behavior of novel lubricants with low viscosity to be used in new-age electric vehicle applications covering a wide range of operating conditions.

Authors:

Anthony Ngo The Ohio State University
Michael Handschuh The Ohio State University