地铁扣件e型弹条受载特征分析  

Analysis on loading characteristics of e-type clip of rail fastener

作　　者：吴浩[1,2] 韦凯[1,2] 郭恭兵 薄栋乾 王平[1,2] WU Hao;WEI Kai;GUO Gongbing;BO Dongqian;WANG Ping(MOE Key Laboratory of High-speed Railway Engineering,Southwest Jiaotong University,Chengdu 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031 [2]西南交通大学土木工程学院,四川成都610031

出　　处：《铁道科学与工程学报》2022年第3期665-673,共9页Journal of Railway Science and Engineering

基　　金：中铁二院铁路扣件系统关键技术创新研究项目(KYY2018108)。

摘　　要：为了科学探究地铁扣件e型弹条真实受载情况下的受载特征,基于DTⅢ型扣件系统建立e型弹条精细化三维有限元模型,结合金属材料塑性变形和断裂机理研究中的应力状态参数概念,计算分析正常安装状态与共振状态下弹条的断裂危险位置和断裂类型。研究结果表明:弹条现场断裂位置普遍出现在小圆弧与中肢连接处,弹条在正常安装状态下其等效应力最大值出现在小圆弧与跟段连接处,与弹条现场断裂位置不一致,而最大应力三轴度以及最小应力软性系数与现场断裂位置高度吻合,表明应力状态参数可以更好地描述弹条的断裂危险点。在钢轨波磨引发的共振条件下,弹条最大应力三轴度以及最小应力软性系数同样出现在小圆弧与中肢连接处,并且弹条最大应力三轴度增大60.3%,最小应力软性系数减少5.4%,弹条更易于发生脆性断裂。弹条小圆弧与中肢连接处横断面的罗德系数显示,小圆弧内侧约等于1,外侧约等于-1,这表明此处横断面受弯曲应力作用。e型弹条在钢轨波磨引起的共振条件下,弹条小圆弧与中肢连接处易于产生微裂纹,同时小圆弧内侧拉应力场会加速裂纹扩展,从而导致弹条瞬间脆断。To explore the loading characteristics of e-type clip of subway fastener under real loading, a refined three-dimensional finite element model of e-type clip was established based on DT Ⅲ fastener system. Combined with the concept of stress state parameters in the study of plastic deformation and fracture mechanism of metal materials, the fracture dangerous position and fracture type of clip under normal installation state and resonance state were calculated and analyzed. The results show that the on-site fracture location of the clip generally appears at the connection between the small arc and the middle limb. Under the normal installation state, the maximum equivalent stress of the clip appears at the connection between the small arc and the heel section, which is inconsistent with the on-site fracture location of the clip, while the maximum stress triaxiality and the minimum stress soft coefficient are highly consistent with the on-site fracture location. This shows that the stress state parameters can better describe the fracture risk point of the clip. Under the resonance condition caused by rail wave wear, the maximum stress triaxiality and the minimum stress soft coefficient of the clip also appear at the connection between the small arc and the middle limb. The maximum stress triaxiality of the clip increases by 60.3% and the minimum stress soft coefficient decreases by 5.4%. The clip is more prone to brittle fracture. The Roeder coefficient of the cross section at the connection between the clip small arc and the middle limb shows that the inner side of the small arc is about 1 and the outer side is about-1, indicating that the cross section here is subject to bending stress. Under the resonance condition caused by rail wave wear, micro cracks are easy to occur at the connection between the small arc and the middle limb of the e-type clip. At the same time, the tensile stress field inside the small arc will accelerate the crack propagation, resulting in the instantaneous brittle fracture of the clip.

关 键 词：e型弹条 应力三轴度 罗德参数 软性系数 脆性断裂 

分 类 号：U213.531[交通运输工程—道路与铁道工程]