Study On Polycrystalline Micro Modeling And Crystal Plastic Finite Element Method Of High Manganese Steel

China’s railway transportation business is developing towards high speed,heavy load and high density,which increases the cost of railway crossing maintenance and replacement.Under the cyclic load and rolling contact load,high manganese steel crossing will produce serious residual stress and plastic deformation,resulting in rolling contact fatigue failure.At the same time,the high manganese steel for crossing is a kind of polycrystalline metal material.Therefore,it is very necessary to study the failure mechanism of high manganese steel for crossing from the meso level.In this paper,considering the influence of microstructure and micro deformation mechanism of the high manganese steel on micro mechanical response,starting from the physical mechanism of plastic deformation of the high manganese steel,the crystal plastic cyclic constitutive model is constructed by ABAQUS User-Defined Material subroutine(UMAT),The polycrystalline micro polycrystalline model of the high manganese steel is established by VORONOI algorithm.Based on the experimental results,the material parameters of the crystal plastic constitutive model of high manganese steel are fitted.The cyclic deformation behavior of the high manganese steel polycrystal model under strain cyclic load is studied by the crystal plastic finite element method.The variations of internal equivalent stress and effective plastic strain of the high manganese steel polycrystal model with the number of load cycles are given.Through the modeling of polycrystalline with defective holes,the cyclic stress-strain response of polycrystalline holes under cyclic strain load is studied.The rolling contact polycrystal model of the high manganese steel was established,and the variations of the equivalent contact stress,equivalent residual stress and effective plastic strain with the number of the rolling load cycles were studied.The ratcheting behavior of different grains in polycrystalline model under rolling load was studied.The polycrystalline model with defective holes is established,and the variations of the equivalent contact stress,equivalent residual stress and effective plastic strain with the number of rolling cycles are studied.The ratcheting behavior of different grains at the defect hole was studied.The polycrystalline micro model,plastic constitutive model parameters and numerical calculation results of the high manganese steel proposed in this paper provide a mechanical basis for revealing the failure mechanism of the high manganese steel from the microstructure level.