A Calibrated Modelling Approach for Predicting Dry Friction Wear of Copper-Free Composite Friction Materials

Area of Science:

• Materials Science
• Tribology
• Mechanical Engineering

Background:

• Composite friction materials are crucial for braking systems.
• Copper is traditionally used but faces environmental concerns.
• Developing effective copper-free alternatives is a key research area.

Purpose of the Study:

• To present a calibrated modelling approach for predicting abrasive wear in copper-free composite friction materials.
• To evaluate the wear performance of formulations where copper is replaced by aluminum/polytetrafluoroethylene (Al/PTFE) ratios.
• To develop and compare predictive models for wear rate.

Main Methods:

• Dry ball-cratering tests were conducted to measure the apparent wear-rate coefficient.
• Four composite formulations were analyzed: one copper-containing reference and three experimental copper-free variants.
• Four calibrated predictive models were developed and compared using experimental data.

Main Results:

• Copper-free formulations exhibited higher wear-rate coefficients (90.579–111.811 × 10^-14 m²·N^-1) compared to the copper-containing reference (80.655 × 10^-14 m²·N^-1).
• Copper replacement increased the apparent wear-rate coefficient by approximately 12–39%, contingent on the Al/PTFE ratio.
• The modified Hertz-Archard model demonstrated the best agreement with experimental data, achieving a Mean Absolute Percentage Error (MAPE) of 1.5%.

Conclusions:

• The proposed calibration framework effectively supports the preliminary screening and ranking of copper-free friction material formulations.
• The modified Hertz-Archard model accurately predicts abrasive wear under dry ball-cratering conditions.
• This research facilitates the development of environmentally friendlier friction materials without compromising performance prediction.