挑臂式钢箱梁面板-中纵梁构造细节疲劳性能研究及构造参数分析  

Research on Fatigue Performance and Structural Parameter Analysis of the Structural Detail of Panel-longitudinal Beam of Cantilever Steel Box Girder

作　　者：杨永清[1] 李国强 洪彧[1] YANG Yongqing;LI Guoqiang;HONG Yu(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,成都610031

出　　处：《铁道标准设计》2023年第5期73-79,共7页Railway Standard Design

基　　金：中铁第四勘察设计院集团有限公司科技研究开发计划课题(2020K001)。

摘　　要：为研究挑臂式面板-中纵梁构造细节的疲劳特性,运用大型通用有限元软件ANSYS建立精细化分析模型,结合热点应力法、Palmgren-Miner线性累积损伤理论及雨流计数法对该构造细节进行横纵向疲劳车加载应力结果计算分析,并开展构造参数影响研究。研究结果表明,轮载作用下该细节经历多次应力循环,应力影响线具有明显的轴重识别效果,采用横向应力/竖向应力研究其疲劳特性是合适的;该细节面板焊趾较腹板焊趾应力水平高,更易发生疲劳开裂,而腹板处焊趾具有无限寿命;面板厚度从12 mm增加到20 mm,面板焊趾和腹板焊趾热点应力分别降低55%和40%,中纵梁腹板与附近U肋的间距从250 mm增加到400 mm,面板焊趾和腹板焊趾热点应力增幅达61%和58%,而中纵梁腹板厚度从12 mm变化到20 mm,面板焊趾处和腹板焊趾处的热点应力基本不变,维持在53 MPa和22 MPa左右。建议在充分考虑安全性和经济性的情况下,合理选择面板厚度及中纵梁腹板与附近U肋的间距以提高面板-中纵梁构造细节的疲劳寿命。In order to study the fatigue characteristics of the structural details of the panel-longitudinal beam in cantilever steel box girder,the large-scale general finite element software ANSYS is used to establish a refined analysis model combined with the hot spot stress method,the Palmgren-Miner linear cumulative damage theory and the rain flow counting method to the structure.The calculation and analysis of the load stress results of the transverse and longitudinal fatigue car are carried out,and the influences of the structural parameters are studied.The research results show that the details have undergone multiple stress cycles under the action of wheel load,and the stress influence line has an obvious axle load identification effect.It is appropriate to use transverse stress/vertical stress to study its fatigue characteristics;the panel weld toe is more stressful than the web weld toe in the detail and more prone to fatigue cracking,and the weld toe at the web has an infinite life;when the thickness of the panel is increased from 12 mm to 20 mm,the hot spot stresses of the panel weld toe and the web weld toe are reduced by 55%and 40%respectively.When the distance between the web of the longitudinal beam and the U ribs is increased from 250 mm to 400 mm,the hot spot stresses of the panel welding toe and the web welding toe are increased by 61%and 58%,while the web thickness of the longitudinal beam is changed from 12 mm to 20 mm,the hot spot stresses at the welding toe of the panel and that of the web are basically unchanged and maintained at about 53 MPa and 22 MPa.It is recommended that the thickness of the panel and the distance between the web of the longitudinal beam and the nearby U-rib should be reasonably selected with full consideration of safety and economy so as to improve the fatigue life of the structural details of the panel and the longitudinal beam.

关 键 词：公铁两用桥 挑臂式钢箱梁 中纵梁 热点应力法 疲劳性能 参数分析 ANSYS 

分 类 号：U448.121[建筑科学—桥梁与隧道工程] U448.213[交通运输工程—道路与铁道工程] U441.4