NUMERICAL CALCULATION METHODOLOGY FOR STRESS INTENSITY FACTORS OF CFCHS WELDED T-JOINTS

A truss made of circular hollow sections (CHS) in which the chord member is filled with concrete is a new kind of structure. In need of fatigue behavior assessment by means of fracture mechanics, the numerical calculation methodology for the stress intensity factors (SIF) of welded T-joints under brace axial tension is discussed in this paper. Firstly, the semi-elliptical surface crack model used for fracture mechanics analysis of the joint is presented on the basis of experimental results of hot spot stress distributions and fatigue cracks. Secondly, the parameter transformation equations for the chord, brace and concrete are deduced. Then, finite element models and singularity elements near the crack front are constructed using APDL of the software ANSYS. Finally, a displacement extrapolation method is used to calculate the SIF. It is concluded that the finite element modeling is reliable and the numerical calculation method is practicable.