Abstract
Detailed two-dimensional finite element models are applied to investigate the fracture behavior of welded beam-to-column connections which are widely used in steel structures in China. The elastic stress intensity factor (KI) and inelastic J-integral (JI) around the crack tip are calculated to provide quantitative estimates of fracture toughness requirements in the connections with different configurations. Four types of weld access holes are modeled after the full-scale connection tests. Subsequently, several connection details including weld flaw size and location, weld backing bar, fillet reinforcement and other modifications, are examined in the effectiveness of reducing the toughness demands on the weld. The analyses have confirmed the observations from connection cyclic tests that the fracture is more likely to occur at the beam flange weld heat affected zone (HAZ) which sustains extensive yielding and exhibits relatively low fracture toughness. The weld flaw size and location have shown significant effects on the toughness requirements both by elastic and inelastic analyses. The modification of removing backing bar and reinforcing a fillet weld shows the most effective approach to reduce the toughness demands. By inelastic analyses, the initial weld defect at HAZ (10 mm away from the column face) shows more toughness demands than that at the interface of the column flange and weld. The evaluated moment at column face when crack predicted to propagate, agrees well with the ultimate moment obtained from the connection tests.
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Wang, Y., Zhou, H., Shi, Y. et al. Fracture behavior analyses of welded beam-to-column connections based on elastic and inelastic fracture mechanics. International Journal of Steel Structures 10, 253–265 (2010). https://doi.org/10.1007/BF03215835
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DOI: https://doi.org/10.1007/BF03215835