Effects of non-Gaussian counter-surface roughness parameters on wear of engineering polymers

• Simple analytical forms of abrasive and fatigue wear equations have been derived for polymers against hard metal counterfaces.
• Weibull distribution has been used for modeling non-Gaussian counter-surface roughness.
• Non-Gaussian counter-surfaces have been categorized in two classes.
• Certain combinations of standard deviation, skewness, and kurtosis of counter-surfaces have been found to meliorate wear resistance.
• A predictive wear severity chart has been proposed for polymer–metal interfaces in low load and low speed applications.

This work was aimed to study on how wear of engineering polymers depends on the topography of counter-surfaces of non-Gaussian type. Instead of widely used Gaussian distribution of surface heights, the Weibull distribution was used here to model asperity heights distribution of the counter-surface. The key surface roughness parameters to characterize the distribution were chosen to be standard deviation, skewness, and kurtosis. Corresponding Weibull parameters were evaluated from both skewness and kurtosis values according to a customized methodology. Some basic wear equations have been extended and modified with Weibull distribution of asperity heights. Study revealed that all of the three surface roughness parameters of hard metal counter-surface substantially influence wear of soft polymers. Experiments have also been carried out with PEEK pins rubbing on 316L stainless steel disc in a typical pin-on-disc setup, and meaningful agreement was noted between some experimental findings and theoretical predictions. A wear severity chart for polymer while rubbed against hard metal surfaces under low load and speed was proposed from the comparative deliberations.