1. An Investigation into Experimental Wear Coefficient Determinations for PTFE Based, Self-Lubricating, Bearing Materials in Sliding Contact Chris Wowk Friction, Wear, and Lubrication of Materials MANE 6960 December 9, 2013

2. Wear Coefficient Calculation US Army Corps of Engineers test data only reported depth of wear per 100 test hours – Test set up pressure and velocity known Assume an adhesive wear model in the region of mild wear Use Archard’s law modification to calculate the dimensional wear coefficient, K, in mm 3 N -1 m -1. Dimensional Wear Coefficient Reported wear rate Test Setup design pressure and speed

3. Comparison of Wear Coefficients

4. Possible Reasons for Different Wear Coefficients LSU testing used generic PTFE composites. It is expected for commercial (proprietary) bearing materials to have performance benefits LSU and Gdansk University testing do not allow for separation between “run in” period and mild wear region of PTFE composites -Army Testing -LSU/Gdansk Testing Slope of Line is K

5. ABAQUS Contact Modeling Shaft Bearing Material Bearing Backing/ Holder Pressure Load Contact along entire width of bearing Contact at edge of bearing due to misalignment Approximately ¼ width of bearing Aligned Bearing Misaligned Bearing ABAQUS Model

6. Misaligned Wear Predicted vs. Actual