正交异性钢桥面肋-板焊接残余应力的数值模拟

Numerical Simulation of Residual Stress in Rib-to-Top Plate Welding of Orthotropic Steel Bridge Deck

由于正交异性钢桥面U肋与顶板焊后残余应力分布复杂,采用解析方法无法求解,为此,采用有限元热-力耦合分析技术对其温度场和应力场进行数值模拟。利用ANSYS有限元软件建立顶板厚16mm、U肋厚8mm的正交异性桥面板双层焊缝模型。引入高温条件下Q345q钢的力学性能参数,考虑焊接电流、电压、焊接速度,对焊接过程进行数值模拟。通过控制热源移动加载,计算出合理的焊接温度场;利用热-力耦合分析技术,调用温度场计算结果,分析得到焊接残余应力场分布。计算结果表明:有限元数值模拟技术可以用于焊接结构残余应力分析;焊缝处不均匀加热与放热导致焊缝中部垂直焊缝方向及沿板厚方向存在较大残余应力,设计时应充分考虑残余应力对结构力学行为的影响。

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.