Evaluating stress intensity factors for surface cracks in an orthotropic steel deck accounting for the welding residual stresses

Abstract

The welding residual stresses (WRSs) in an orthotropic steel deck were investigated via experimental measurement and finite-element simulation. Both the surface and through-thickness WRSs were obtained. The simulated residual stress fields were in reasonable agreement with the measured results. The weight function method (WFM) was then adopted to investigate the effects of WRSs on stress intensity factors (SIFs) of semi-elliptical surface crack. The surface crack was subjected to a combination of far-field load and through-thickness WRSs, and different crack aspect ratios and relative depths were analyzed. The results reveal that the transverse residual stresses have prominent effects on SIFs: for the surface point, which is always located in the tensile stress region, its SIFs increase substantially with crack growing (a/t increasing); for the deepest point, WRSs lead to some SIFs increase with lower growth rate and some SIFs decrease continuously. This is due to that, as a/t increasing, the WRS level at crack tip location gradually decreases from the high tensile stress region, even into the compressive stress region.