Experimental thermal fatigue crack on brake disc of heavy vehicle

Brake system reliability is critical for the safety and performance of heavy vehicles, including semi-trailers, passenger buses, and industrial transport units. This study investigates the thermal fatigue failure mechanisms in brake discs (BDs), which are subjected to extreme operational conditions. The primary motivation is to enhance brake disc durability and reduce the risk of catastrophic failures by understanding the interplay between material properties, thermal stress, and fatigue resistance. A comprehensive experimental approach was employed, including visual inspections, chemical composition analysis, metallurgical structure examination, hardness testing, and tensile strength evaluation. The study compares brake discs that have undergone extensive service with those in an undamaged state to identify critical degradation patterns. The results indicate that temperature fluctuations and cyclic thermal stresses induce crack formation and propagation, with rough graphite inclusions significantly reducing fatigue strength. Furthermore, deviations in silicon and carbon content were found to impact material integrity, contributing to premature failure. The findings of this research provide actionable insights for optimizing brake disc design, material composition, and manufacturing processes. By modifying graphite distribution, refining alloy compositions, and improving thermal resistance, future brake systems can achieve greater durability and reliability. These advancements will directly enhance braking efficiency, reduce maintenance costs, and improve overall vehicle safety.