Yield line patterns of T-stubs connected by thread-fixed one-side bolts under tension

Abstract

Yield line patterns of T-stubs connected by thread-fixed one-side bolts (TFOSBs) are investigated when they fail due to complete flange yielding under tension using finite element analysis. Parametric studies are carried out to compare T-stubs connected by TFOSBs and those connected by nut-fixed bolts. Effects of the flange width, the flange thickness, the bolt middle distance, the bolt end distance and the bolt diameter on the yield line patterns and yield tensile strengths are presented. Analysis results show that the yield tensile strength of T-stubs connected by TFOSBs is slightly lower than that of T-stubs connected by nut-fixed bolts. The flange width is the main factor that affects the yield line patterns of T-stubs connected by TFOSBs. For T-stubs having flange width to length ratios within the range studied here, with the increase in flange width, the yield line pattern gradually changes from a double curvature yield line pattern to a non-circular end yield line pattern, then to a circular individual end yield line pattern, and eventually to a bolt hole circular yield line pattern. And for T-stubs having flange width to length ratios within the range studied here, effects of bolt end distance e on the yield line pattern depends on the flange width L. The current design method gives a reasonably conservative estimation of the tensile strengths of T-stubs connected by TFOSBs.