Study On Abrasive Wear Characteristics And Mechanism Of Rail Vehicle Brake Disc

Brake disc is a key component of rail vehicle disc brake device.Its tribological characteristics have important influence on braking performance of rail vehicle foundation brake system.Cast iron is a kind of brake disc commonly used in rail vehicle braking system because of its low production cost and mature processing technology.In this paper,the abrasive wear characteristics of the cast iron brake discs in the high cold and windy areas of China are studied in the course of service.The abrasive wear characteristics and mechanism of the cast iron brake discs are studied by the combination of single abrasive particle erasing test and simulation.A simulation analysis model of cast iron brake disc material is established by coupling the finite element method with the smoothed particle hydrodynamics method.The results show that the coupling between finite element mesh and SPH particles can be achieved effectively and accurately.Moreover,the trajectories of SPH particles can accurately describe elastic-plastic fracture behavior of brake discs.Through the simulation of single abrasive particle erasing,the erasing deformation behavior and the formation mechanism of the surface morphology of the brake disc materials are studied,and the influence of the rubbing speed and erasing depth of the abrasive particles on the erasing force and the erasing heat are analyzed.The simulation results show that the ploughing and cutting effects of single abrasive particles make the brake disc material plastic deformation,tear and crumble to form grooves and ploughs,and the rubbing force of the abrasive grain increases with the increase of the erasing depth,but the friction speed has little effect on the erasing force;the rubbing temperature of the abrasive grains along with the erasing speed.Increase and increase,but scratching depth has little effect on scratching temperature.The grinding and ploughing of abrasive particles not only cause the surface damage of the brake disc,but also produce erasing force and heat stroke,which will have an important influence on the braking efficiency of the brake system.Design a single abrasive scratch test tool and clamp device,and build a single abrasive wear test platform on the vertical machining center.A single abrasive scratch test with different scratching depth and speed was carried out.After the test,the surface morphology,cross section morphology and microstructure of the brake disc were observed and measured by light microscopy,scanning electron microscopy and three-dimensional profilometer.The results show that the surface morphology of scratch is formed by plastic deformation,tearing and breaking of the cast iron.With the increase of the erasing speed,the surface defects,such as holes and micro cracks on the scratched surface,are reduced,and the thickness of the crushed deformation layer becomes smaller.With the increase of abrasive scratch depth,the plough wrinkles on both sides of the groove become larger,the surface defects become more serious,and the thickness of the crushed deformation layer becomes larger.The abrasive wear mechanism of the brake disc in the rain environment is relatively complex.It is found that the thickness of the crushed deformation layer is smaller in the rain environment,and the wear surface of the abrasive wear surface is more prone to wear.In this paper,the abrasive wear characteristics and mechanism of the brake disc material under abrasive grain ploughing and cutting are studied by a single abrasive particle erasing test and simulation method.The research results provide a theoretical reference for the design and manufacture of the friction interface of the cold resistant and wind resistant sand brake disc.