FRACTURE BEHAVIOR ANALYSES OF WELDED FLANGE-BOLTED WED CONNECTION OF STEEL STRUCTURE

摘要

Welded flange-bolded wed (WFBW) connections are a common form in steel structure, many times in high intensity seismic displayed the good seismic performance in previous years. However, in the 1994 Northridge earthquake and 1995 Kobe earthquake, brittle fracture still occurred in junction of beam flange and column in the (WFBW) connections, So this is very necessary to use fracture mechanics viewpoint to research fracture toughness of the weld root. In this paper ABAQUS is used to establish three dimensional finite element(3D) model of WFBW, fracture behavior of "artificial crack" of the weld root is analyzed, the stress intensity factor(K) as a fracture mechanics parameters to calculate fracture behavior in the beam flange weld root. Results show that stress intensity factor varies cross the beam flange width, and is largest in the middle of the flange. When selecting the same initial flaw length, the stress intensity factors of bottom flange weld root was significantly higher than in the top flange weld root. The K increases nearly linear with the increase of the initial flaw length. Comparison of 2D and 3D models, when the same initial flaw length, calculation of KΙ/σn the three-dimensional model approximately as 1.5 times as that by two-dimensional model.