Stress intensity factors of surface cracks in welded T-joints between CHS brace and concrete-filled CHS chord
With the increasing use of arch bridges made of welded T-joints between CHS brace and concrete-filled CHS chord (CFCHS) in China, fatigue of the welded CFCHS joints under vehicle loading is becoming an issue to be addressed. Like welded CHS joints, fatigue assessment of the welded CFCHS joints can be performed based on one of three approaches, namely classification method, hot spot stress and fracture mechanics. The last one is the advanced approach in which the parameter of dominating fatigue crack propa-gation, Stress Intensity Factor (SIF), needs to be determined first. This paper presents the simplified fracture mechanics model, the FE methodology predicting stress intensity factors of the welded CFCHS joint with semi-elliptical surface cracks under axial brace loading. In this method the software ANSYS was used to produce thefinite element model of the T-joint. The special APDL programs were developed to generate the surface semi-elliptical weld toe cracks at the crown of the joint and to create wedge-shaped singularity elements around thecrack tip since they are not available in ANSYS element library. In order to get reliable and convergent result,the nodes on the interior surface of the steel tube and the nodes on the external surface of the concrete must be in the same location and they shouldnt be merged together. Contact elements were introduced between them. Thestress intensity factors were calculated respectively by the way of displacement extrapolation. The calculatedresults indicate that the finite element modeling is successful and the numerical simulation is an effective way to obtain the stress intensity factors of the complicated CFCHS joints.
M.Gu L.W.Tong X.L.Zhao X.G.Lin
School of Civil Engineering, Tongji University, Shanghai, China School of Civil Engineering, Tongji University, Shanghai China Department of Civil Engineering, Mona School of Urban Construction, Zhejian Shuren University, Hangzhou, China
国际会议
第12届钢管结构国际学术会议(The 12th International Symposium on Tubular Structures)
上海
英文
359-365
2008-10-08（万方平台首次上网日期，不代表论文的发表时间）