焊接产生的残余应力及初弯曲对输电塔承载力的影响研究

Research on Influence of Welding Residual Stress and Initial Bending Caused by Welding on Bearing Capacity of Transmission Tower

在数值模拟软件Abaqus中建立了三处节点为实体单元的输电塔多尺度模型。利用焊接插件AWI模拟输电塔横担、曲臂以及塔身三处节点的焊接过程,得到多尺度模型下三处节点的焊接残余应力分布。对含残余应力的多尺度模型施加垂直于线路方向的静风荷载,得到塔顶点荷载-位移曲线。结果表明,由于残余应力的存在,输电塔的承载力最多可降低8%。单独模拟包含整根主材节点处的焊接过程,提取节点处各管轴线交点的位移值,从而确定由于焊接对主材造成的初弯曲值,将得到的初弯曲值施加到输电塔宏观模型中,得到焊接初弯曲影响下的输电塔荷载-位移曲线,结果显示,由于焊接产生的初弯曲对输电塔承载力的降低最多可达2.38%。

In the numerical simulation software Abaqus,the multi-scale model of transmission tower taking three joints as solid units was established.The welding process of three joints of cross arm,curved arm and tower body of transmission tower using welding plug-in AWI was simulated,and the distribution of residual stress of the three joints of the multi-scale model was obtained.The multi-scale model with residual stress was applied to static wind loads perpendicular to the line direction,and the load-displacement curves of the tower top point were obtained.The results show that the bearing capacity of the tower can reduce by up to 8%because of the residual stress in the transmission tower.The welding process at the joints containing the whole main materials was simulated separately,and the displacement values at the intersection point of each pipe axis at the joints were extracted to determine the initial bending values due to welding of the main materials,and the obtained initial bending values were applied to the macro model of the transmission tower.The load-displacement curves of the transmission towers under the influence of initial bending were obtained.The results show that the reduction of the bearing capacity of the transmission tower can be as high as 2.38%because of the initial bending caused by welding.