2018, Goli, M.

PROJECT TITLE (BSc, 2016-2018): Root Cause Analysis of a Failure in an Automotive Disc Brake

This study investigates a failure in a disc brake in an automobile. The failed brake disc has been in service for approximately 10 years. The observed failure is in the form of radial cracks which appeared to be initiated at the outer edge of the disc brake. Cracks are rather straight with no branching. Optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD) analysis, and energy dispersive X-ray spectroscopy (EDS) were used to study the microstructure of the failed disc. Vickers microhardness test was also used to evaluate the hardness of samples. Results show that the root cause of crack formation in this case is related to the excessive wear in the brake disc. Different wear mechanisms, namely abrasive and adhesive wears, were recognized in the failed specimen. Also, the worn surface in some areas is covered with fine oxide particles. These particles are appeared to have a significant contribution to the abrasion. To further understand the wear mechanisms, pin-on-disc experiments were also conducted on samples. Results of pin-on-disc experiments were compared and correlated to the results, obtained from the failed brake disc.

Papers:

Wear Induced Failure of Automotive Disc Brakes—A Case Study, Materials 2019