Numerical Study On The Mechanical Properties Of Bainite Steel Crossing Under Contact Wheel Load

Railway is the national important foundation facilities. A crossing is the equipment to make train travel orbit, which is one of the most easily damaged components in railway structures. With the development of society, the high demand of heavy load and high speed is increasingly grow, which may bring challenges to safety, high efficiency and economy. A bainitic steel crossing is assembled by the bainitic steel nose rail, the high carbon steel fork with rail and the wing rail, which has characteristics of high strength and high wear resistance. C ompared to traditional high manganese steel, a bainitic steel crossing has a longer lifetime and ha s higher cost performance, which is widely used to bring greater social benefits.During complicated service loading conditions, the bainitic steel crossing prone to wear for wing rail and fatigue spalling for nose rail, which affects their lifetime and safety of train travel. Stress/strain analysis is the key to study wear and fatigue spalling of a crossing. Therefore, it is very important to discuss the distribution laws of stress field, plastic strain field, displacement field and residual stress field of the wing rail and nose rail.In this thesis, a three-dimensional model of the 60 kg/m and number 12 bainitic steel assembled crossing is established by using UG software. Then by using ANSYS/DYNA FEM software, the numerical study is conducted and detailed analysis carried out as follows: the process analyses when a wheel passes a the bainitic steel crossing; the stress, strain and vertical displacement in the nose rail and wing rail under different matches of yield strength and elastic modulus; residual stress and plastic strain in nose rail and wing rail under cyclic loads; dynamic response of the crossing under an impact load. The thesis summarizes the influence of the yield strength, elastic modulus, cyclic loads and impact load on the mechanical properties of the bainitic steel crossing. Free vibration and forced vibration are analyzed for the bainitic steel crossing. Compared with other literature, it is found that the proposed analysis methods can correctly applied to the research and the obtained results can provide mechanical reference for failure analysis and strength design of the bainitic steel assembled crossing.