Modeling of safety assessment and useful life time of high-speed passenger car brake discs

The useful life of a passenger car brake disc design was investigated using fracture mechanics theory to analyze the structure integrity of the brake disc with a crack-like flaw.The disc failure mechanism was predicted using failure states analysis and finite element simulations of the transient stress field to develop a safety assessment model and to predict the brake disc life time.The failure mechanism is due to cycle fatigue stress including thermal stresses and residual stresses induced by the braking procedure.A fatigue crack initializes from a subsurface flaw in the brake disc and then propagates towards the brake disc surface.The detailed model includes the working plane,the operating stress,the fracture parameter,the evaluation procedure and the assessment criterion.The results show that the method can be used to design and evaluate brake discs and to determine repair periods to provide guidance for safety assessments and life time predictions of brake discs for high-speed passenger cars and other vehicles.