考虑焊接残余应力的钢桥面板U肋焊接处局部应力分析

In order to study the local strress characteristics at weld joints between the top plate and U-rib of Orthotropic steel deck under welding residual stress and the combination of external loads and welding residual stresses, taking a wide body steel box girder as an example, the numerical simulation of welding process of the welding seams was carried out based on thermo elastic-plastic finite element theory. The changes of temperature field and stress field in welding process were analyzed. The combination of welding residual stress and external loads was realized by the method of initial stress. The results show that the peak value of the residual tensile stress perpendicular to the direction of the weld at the bottom of the steel deck is close to the yield strength of the material, and the stress in the area far away from the weld seam decreases sharply. The transverse residual stress at the weld toe is obviously greater than that at the weld root. From top surface to bottom surface of the steel deck, the longitudinal residual stress changes from compressive stress to tensile stress, and the change trend of the transverse residual stress is "tensile stress to compressive stress to tensile stress". Considering the residual stress in the way of initial stress, the relative error of stable stress field can be controlled within 5.0%. The influence of self weight and secondary dead load on the distribution characteristics of local stress field and the extreme value of stress at weld root and weld toe is not significant (within 1.7%). When the local symmetrical wheel loads is considered in the external load but the dissipation of residual stress under the external loads is not considered, the maximum value of transverse stress perpendicular to the weld at the weld root and weld toe can be increased by 10.7% and 17.6% respectively. Under welding residual stress and the combination of external loads and welding residual stresses, the distribution of the stress along the thickness of the top plate at the weld toe and weld root are in accordance with the rule of "straight line and parabola".