Chris Wowk Friction, Wear, and Lubrication of Materials MANE 6960 December 9, 2013

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 mm3 N-1 m-1 . Reported wear rate Test Setup design pressure and speed Dimensional Wear Coefficient

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

6. Misaligned Wear Predicted vs. Actual