CAJ | 학술논문

本文建立由铁路辙叉和列车车轮组成的三维弹‐塑性有限元模型，研究高锰钢辙叉心轨的应力／应变场。文中考虑辙叉心轨在顶宽50 m m处的两种服役状态———服役前期未发生加工硬化和服役后期发生加工硬化，分析加工硬化对心轨应力／应变大小和分布的影响。对服役加工硬化的情况，考虑到距离工作表面不同深度处辙叉材料性能的不同，将心轨局部模型分层，并设置各层的材料性能；对未发生加工硬化的情况，为模型设置均匀的材料性能。结果表明，两种服役状态下辙叉心轨的von Mises应力和等效塑性应变均随深度的增加先快速增大，然后逐渐减小；与服役初期相比，服役后期心轨的最大等效应力增大约23％，最大等效塑性应变则降低约40％；塑性变形区域也明显减小，这是由于心轨在服役加工硬化后屈服强度已大幅提高。因此，在很大程度上，服役后期的加工硬化起着抑制心轨顶面塌陷和飞边形成的作用。此外，与未加工硬化心轨相比，加工硬化后心轨的最大等效应变与工作表面的距离由0.8 mm增大到了1.5 mm ，这表明易产生裂纹的位置有远离心轨表面的趋势。
본문건립유철로철차화열차차륜조성적삼유탄‐소성유한원모형，연구고맹강철차심궤적응력／응변장。문중고필철차심궤재정관50 m m처적량충복역상태———복역전기미발생가공경화화복역후기발생가공경화，분석가공경화대심궤응력／응변대소화분포적영향。대복역가공경화적정황，고필도거리공작표면불동심도처철차재료성능적불동，장심궤국부모형분층，병설치각층적재료성능；대미발생가공경화적정황，위모형설치균균적재료성능。결과표명，량충복역상태하철차심궤적von Mises응력화등효소성응변균수심도적증가선쾌속증대，연후축점감소；여복역초기상비，복역후기심궤적최대등효응력증대약23％，최대등효소성응변칙강저약40％；소성변형구역야명현감소，저시유우심궤재복역가공경화후굴복강도이대폭제고。인차，재흔대정도상，복역후기적가공경화기착억제심궤정면탑함화비변형성적작용。차외，여미가공경화심궤상비，가공경화후심궤적최대등효응변여공작표면적거리유0.8 mm증대도료1.5 mm ，저표명역산생렬문적위치유원리심궤표면적추세。
A three dimensional elastic‐plastic finite element model consisting of a railway crossing and a train wheel was established to investigate the stress/strain field in a high manganese steel crossing nose . Two serv‐ice states of the crossing at a nose width of 50 mm were considered in the paper ,i.e.non‐work hardening cor‐responding to the early service stage and work hardening corresponding to the later service stage ,and the in‐fluence of service work hardening on the magnitude and distribution of stress/strain in the crossing nose was analyzed .In the case of simulation of service work hardening ,a layered model was constructed and various material properties were assigned to corresponding layers ,according to the effect of the distance from the sur‐face of an actual work‐hardened crossing nose on the material properties ,while a homogeneous material prop‐erty was assigned to the entire model with non‐work hardening . The results indicate that ,during both the ear‐ly and later service stages , the von Mises stress and equivalent plastic strain rapidly increase and then gradually decrease with the increase of the depth . As compared with the early service stage , during the later service stage ,the maximum von Mises stress of the crossing nose increased by about 23% ,while the maximum equiv‐alent plastic strain decreased by about 40% ,and the plastic strain zone reduced significantly . The reason for this is due to the largely increased yield strength of the crossing nose after service work hardening .It is there‐ <br> fore believed that the surface quashing and the formation of overlap in the crossing nose may be largely sup‐pressed owing to the service work hardening . Furthermore , as compared to the non‐work‐hardened crossing nose , the distance between the location of the maximum equivalent plastic strain of the work‐hardened crossing nose and the surface of the crossing nose increases from 0.8 mm to 1.5 mm ,indicating that crack initiation site tends to move to locations farther away from the crossing nose surface .