考虑残余应力影响的索梁锚固区焊缝疲劳寿命预测  

Fatigue life prediction of welds in cable girder anchorage zone considering residual stress

作　　者：殷志欢 张鹏飞 常军[1] 袁鑫[1] YIN Zhihuan;ZHANG Pengfei;CHANG Jun;YUAN Xin(College of Civil Engineering,Suzhou University of Science and Technology,Suzhou 215011,China)

机构地区：[1]苏州科技大学土木工程学院,江苏苏州215011

出　　处：《扬州大学学报（自然科学版）》2022年第1期61-67,共7页Journal of Yangzhou University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51508368);江苏省研究生科研与实践创新计划资助项目(SJCX20_1112)。

摘　　要：为评估残余应力影响下的索梁锚固区焊接细节处的疲劳寿命,以苏通长江大桥为工程背景,建立索梁锚固区精细化有限元模型,采用生死单元法模拟焊接过程,得到焊趾处的残余应力分布.通过在焊趾附近施加局部锤击力,数值模拟高温锤击处理对焊接细节残余应力分布的影响.基于英国桥梁规范BS5400和欧洲设计规范Eurcode评估考虑残余应力影响的索梁锚固区焊接细节的疲劳寿命.结果表明:钢锚箱直角焊缝附近的残余应力在焊趾处达到峰值,且随着距焊趾处距离的增大而减小;基于BS5400规范,当残余应力为192 MPa时,上锚固板焊接细节处疲劳寿命相比于不计残余应力时的降低了63%,经高温锤击处理后,该处疲劳寿命相比于不计残余应力时仅降低了22%;相比于Eurcode规范,BS5400规范计算的外腹板与下锚固板焊接处的疲劳寿命降低了49%.In view of the complicated stress state of welding details in the cable-beam anchorage zone of long-span cable-stayed bridges,fatigue failure is prone to occur under the combined action of vehicle-mounted and welding residual stress.In order to evaluate the fatigue life of the welding details of the cable grider anchorage zone considering the influence of residual stress,the Sutong Yangtze River Bridge was used as the engineering background,a refined finite element model of the cable girder anchorage zone is established.The welding process is simulated by the life-death element method,and the residual stress distribution at the toe is obtained;a local hammering force is applied near the weld toe,the influence of high-temperature hammering treatment on the residual stress distribution of welding details is obtained through numerical sumulation.Finally,the fatigue life of the welding details of the cable-beam anchorage zone considering the influence of the residual stress is analyzed based on the BS5400 standard and the Eurcode standard.The results show that the residual stress near the right-angle weld of the steel anchor box reaches the peak at the weld toe,and decreases with the increase of the distance from the weld toe;based on the BS5400 specification,when the residual stress is 192 MPa,the fatigue life of the welding details of the upper anchor plate is reduced by 63%compared with that without residual stress;after high temperature hammering treatment,the influence of residual stress on the fatigue life of the welding details of the upper anchor plate is reduced to 22%;the fatigue life of the welded details of the outer web and the lower anchor plate calculated based on the BS5400 standard is reduced by 49%compared with the fatigue life calculated based on the Eurcode standard.

关 键 词：索梁锚固区 焊接残余应力 名义应力法 疲劳寿命 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]