Q420厚板焊接大规格角钢残余应力峰值及分布

Distribution Feature of Residual Stress in Q420 Welded Large Angle Members for UHV Transmission Towers

特高压输电杆塔中采用高强度大规格角钢具有良好的经济性,采用钢板焊接的方式能有效解决采购困难的问题。但目前针对焊接大规格角钢承载力的研究较少,对其焊接残余应力的研究更是匮乏。为研究焊接大规格角钢残余应力分布特征,根据现有焊接大规格角钢加工实际情况,采用数值方法分别计算不同屈服强度(fy)的L250、L280、L300肢宽角钢焊接后的温度场、应力场。结果表明:不同屈服强度下焊缝残余拉应力均超过屈服强度,屈服强度较低时残余压应力比(β)更高;残余应力分布于角钢宽厚比(b/t)有关,宽厚比增加后峰值点β减小、更向角钢棱线靠近。给出适用的残余应力分布模型,为进一步研究此此类构件稳定承载力提供参考。

When compared with composite section member,the joint is simplified for single large width angle member used in UHV transmission tower,and the difficulty in purchasing members could be solved by thick plate welding method.As a result of deficiency in residual stress distribution,there are few research on welded large angle members capacity.A finite element analysis study is conducted for such kind of members,and the welding parameters in models are identical with factory procedure.Models cover L250,L280 and L300 series angles with different yield stress.The results derived from this research are listed as follows:for all models the stress exceed yield strength(fy)in welding seam region,and residual compressive stress ratio(β)is higher for members with lower fy;the distribution of residual stress is related to width-thickness ratio(b/t),the magnitude of peak point decreases when b/t ratio rises.The residual distribution pattern is proposed for welded large angle members,serving as a reference for researching on stability bearing capacity of such members.