【摘要】 为了研究钢桥对接焊接接头温度场、残余应力场和变形场的分布规律，利用有限元软件建立16 mm厚桥钢板对接焊缝三维有限元模型，并通过盲孔法试验实测数据对模型的正确性加以验证.基于此，进一步分析了焊件温度场、残余应力场和变形场的分布规律，并在焊件中引入初始裂缝，探讨了初始缺陷和焊接残余应力对焊缝疲劳寿命的影响.研究结果表明：沿垂直焊缝方向，纵向残余应力呈现拉-压分布状态，焊缝附近60 mm的热影响区内，主要为拉应力，峰值达415 MPa，超过材料的屈服强度，当远离热影响区时，纵向残余拉应力转变为压应力.横向残余应力在焊趾处达到峰值205 MPa.在无约束条件下，焊接引起的变形为典型的平面外角变形，随着与焊缝中心的距离增加，各测点的变形呈线性增长，最大变形出现在焊件外边缘，为14.58 mm.即使是较小的残余应力，无论其状态如何，均会影响疲劳寿命. 3%和8%的残余拉-压应力分别导致疲劳寿命降低16.7%和提高68.4%；残余拉应力随着应力的增大导致疲劳寿命降低，但降低速率逐渐衰减.当拉/压应力数值相近时，压应力对疲劳寿命的影响远大于拉应力.在实际构件的预制过程中，应通过预变形等方法来控制焊件的变形；焊后通过表面处理技术控制残余拉应力，以提高材料的疲劳寿命和延长结构的使用寿命.更多还原

【Abstract】 To investigate the distribution patterns of the temperature field, residual stress field, and deformation field in welded joints of steel bridges, a 3D finite element model of a butt weld in a 16 mm-thick bridge steel plate was established using finite element software. The accuracy of the model was verified through the blindhole method experimental data. Based on this validated model, the distribution characteristics of the temperature field, residual stress field, and deformation field in the welded components were further analyzed. Additionally, an initial crack was introduced into the weldment to explore the impact of initial defects and welding residual stress on the fatigue life of the weld. The study results indicate that along the direction perpendicular to the weld seam, the longitudinal residual stress exhibits a tensile-compressive distribution. Within the 60 mm heat-affected zone near the weld, tensile stress is predominant, with a peak value of 415 MPa, exceeding the yield strength of the material. As the distance from the heat-affected zone increases, the longitudinal tensile residual stress transitions to compressive stress. The transverse residual stress reaches its peak value of 205 MPa at the weld toe. Under unconstrained conditions, the welding-induced deformation presents as typical out-of-plane angular distortion, with deformation at each measurement point increasing linearly with distance from the weld seam center. The maximum deformation occurs at the outer edge of the weldment, measuring 14.58 mm. Even small residual stresses, regardless of their state, influence fatigue life. Residual tensile-compressive stresses of 3% and 8% result in a decrease of 16.7% and an increase of 68.4% in fatigue life, respectively. Residual tensile stress leads to a reduction in fatigue life as stress increases, but the rate of reduction gradually diminishes. When the tensile/compressive stress values are comparable, compressive stress has a far greater impact on fatigue life than tensile stress. During the prefabrication of actual components, methods such as pre-deformation should be employed to control the deformation of the weldment, while post-weld surface treatment techniques should be used to manage residual tensile stress, thereby improving material fatigue life and extending the service life of the structure.更多还原