Numerical simulation of residual stress in rib-to-top plate welding of orthotropic steel bridge deck

Because the residual stress distribution of the welded U ribs and top plate of orthotropic steel bridge deck is complex and the stress distribution can not be solved by the analytical method, the numerical simulation of the temperature fields and stress fields of the welding process of the U ribs and top plate was conducted, using the coupled thermo-mechanical finite element analysis. The finite element software ANSYS was used to set up the models for the double-layer welded joints of the orthotropic steel bridge deck with its top plate being 16 mm thick and U rib being 8 mm thick. The mechanical property parameters of the steel Q345q of high-temperature conditions were introduced and in consideration of the welding current, voltage and welding speed, the numerical simulation of the welding process was also conducted. By way of controlling the heat source moving loading, the reasonable temperature fields of the welding were calculated. The coupled thermo-mechanical finite element analysis was used to adjust the calculation of the temperature fields and the distribution of the residual stress fields of the welding was analyzed and obtained. The results of the calculation indicate that the finite element numerical simulation can be applied to the analysis of the residual stress in the welded structure. The non-uniform heating and the relief of heating of the welded joints can cause the directions of the middle parts of the welded joints that are vertical to the joints and along the plate thickness to have considerable residual stress. In the design, the influences of the residual stress on the mechanical behavior of the structure should be thoroughly considered.