摘要
扣件系统的安装状态直接影响弹条疲劳寿命的预测结果。目前,e型弹条失效及疲劳性能的现有研究大多基于简化加载方式(先将弹条插入插孔,后抬升趾端位移)模拟扣件安装过程,忽略了扳手对弹条中肢的约束,弹条跟端和后拱的逐步抬升及弹条跟端与铁垫板承台之间摩擦的影响。以DT-Ⅲ型扣件系统为例,提出了基于扣件现场安装,拉拔e型弹条中肢的加载方式,建立精细化分析模型,与简化加载工况对比分析,并通过现场安装及简化安装测试验证。结果表明:现场安装应变测试的实测表面最大主应变值与简化加载试验结果相近,但方向角与后者相差约5°。现场安装加载工况的弹条最大主应变全局最大值位置,随弹条插入深度增加而发生显著变化;当弹条处于过安装状态时,应变全局最大值阶跃式增长,位置跳变至弹条中肢与铁垫板插孔挤压处。为准确评估与预测e型弹条疲劳寿命,仅可采用现场安装加载工况进行疲劳分析;若对弹条进行强度大小分析,为节约计算时间,也可采用简化加载工况近似模拟。
The installation state of fastening systems directly affects the fatigue lives of rail clips.Most existing researches on the failure and fatigue lives of e-type clips simulated the installation process of fastening systems based on the simplified loading mode(inserting the rail clip into the jack and then lifting the toe end to move),ignoring those effects on the static behavior of the rail clip,viz.,the constraint of the spanner on the middle leg of the rail clip,the gradual lifting of the heel end and back arch for the rail clip,and the friction between the heel end of the rail clip and the base plate of the iron bottom plate.Taking the DT-Ⅲfastening system as an example,based on the loading mode which is to pull the middle limb of e-type clip in the actual installation process,a fine element model is proposed and the calculation results are compared with those for simplified loading cases.Besides,field and simplified installation experimental verifications are carried out.The results show that:the measured maximum principal strain of field installation case is close to that of a simplified loading case,but the orientation angle differs by about 5°from the latter.In the case of the field installation process,the global maximum position of the maximum principal strain changes significantly with the increased insertion depth of the rail clip.When the rail clip is in an over-installation state,the global maximum position jumps to the place where the middle leg of the rail clip and the jack of the iron base is squeezed,resulting in a step increase.To accurately evaluate and predict the fatigue life of an e-type clip,the fatigue analysis can only be carried out under the actual installation state.A simplified loading condition can be used for approximate simulation when merely analyzing the strength of the clip.
作者
刘艳
刘欢
李秋彤
姜秀杰
袁贤浦
朱哲皓
LIU Yan;LIU Huan;LI Qiu-tong;JIANG Xiu-jie;YUAN Xian-pu;ZHU Zhe-hao(Shanghai Research Institute of Materials,Shanghai 200437,China;Shanghai Engineering Research Center of Earthquake Energy Dissipation,Shanghai 200437,China;School of Environmental and Material Engineering,Shanghai Polytechnic University,Shanghai 201209,China;Ecole des Ponts ParisTech,Laboratorie Navier,Paris 77455,France)
出处
《工程力学》
EI
CSCD
北大核心
2023年第1期238-248,共11页
Engineering Mechanics
基金
上海市青年科技启明星计划项目(19QB1401100)
上海市浦江人才计划项目(20PJ1417300)。
关键词
轨道交通
扣件系统
e型弹条
有限元
应变测试
加载方式
rail transit
fastening system
e-type rail clip
finite element
strain test
loading mode
