基于断裂力学的圆钢管混凝土T型焊接节点疲劳寿命预测  

PREDICTION OF FATIGUE LIFE FOR WELDED T-JOINTS OF CONCRETE-FILLED CIRCULAR HOLLOW SECTIONS BASED ON FRACTURE MECHANICS

作　　者：童乐为[1,2] 顾敏[1,2] 朱俊[3] 王柯[4] 

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]同济大学土木工程学院建筑工程系,上海200092 [3]华东建筑设计研究院有限公司,上海200002 [4]香港大学土木工程系

出　　处：《工程力学》2013年第4期331-336,354,共7页Engineering Mechanics

基　　金：国家自然科学基金项目(50478108)

摘　　要：该文应用线弹性断裂力学基本原理预测圆钢管混凝土桁架焊接T型节点的疲劳寿命。首先,进行了一些节点的疲劳试验,作为验证节点疲劳寿命预测是否可靠的参考数据;其次,建立了基于断裂力学的疲劳寿命数值模拟的模型和流程框图,采用ANSYS软件编制了APDL宏命令,实现了节点疲劳寿命的计算;最后,分析了节点疲劳裂纹的扩展特性。研究结果表明:断裂力学数值模型能较好地预测这种复杂的钢混组合节点的疲劳寿命;在正常的焊接质量条件下,不同的初始裂纹尺度对节点疲劳扩展寿命的影响不大;裂纹在长度方向的扩展速度大于在深度方向的扩展速度;裂纹深度在达到1/2主管壁厚之前,裂纹沿深度方向的扩展非常缓慢,大部分的疲劳寿命消耗在此阶段,之后裂纹沿深度方向的扩展较快。The basic theory of linear elastic fracture mechanics was used to predict the fatigue life of welded T-joints in concrete-filled steel circular hollow section trusses.Firstly,some fatigue tests of the joints was carried out,which would be reference data for the validation of fatigue life prediction.Secondly,a model and a flowchart were set up for the numerical simulation of fatigue life based on fracture mechanics.APDL macro commands were developed by means of the software ANSYS,and then the prediction of fatigue life of the joints was implemented.Finally,the behavior of fatigue crack propagation was investigated.It is concluded that the numerical model based on fracture mechanics can better predict the fatigue life of complicated steel-concrete composite joints.The different size of an initial crack does not cause a significant influence in the condition of normal welding quality.The rate of crack propagation in length is faster than that in depth.Before the depth of a crack come to a half of the chord thickness,the crack propagates quite slowly in depth and a large proportion of fatigue life undergoes this period.Hereafter,it propagates more quickly in the direction of depth.

关 键 词：圆钢管混凝土 T焊接节点 断裂力学模型 疲劳寿命预测 裂纹扩展特性 

分 类 号：TU391[建筑科学—结构工程] TU392.5