Q420高强度厚板焊接大规格角钢轴压稳定承载力研究

RESEARCH ON STABILITY BEARING CAPACITY OF SINGLE ANGLE MEMBERS WELDED Q420 HIGH STRENGTH THICK PLATES UNDER AXIAL COMPRESSION

在特高压输电塔中,焊接大规格角钢能解决热轧大角钢采购困难的问题,目前工程中已经开始相关应用,但对其残余应力分布、稳定承载力的研究较少。针对这一情况,根据焊接角钢加工实际情况,对Q420钢板焊接后的温度场、应力场、截面的焊接残余应力分布进行计算分析。考虑该残余应力和构件初始缺陷建立L250、L280、300、L320、L360肢宽的有限元模型,对厚板焊接角钢构件稳定承载力进行了分析。结果表明:焊接角钢在焊缝位置残余拉应力达到屈服,最大残余压应力约为0. 3f_y,其中f_y为钢材的屈服强度;特高压输电塔中的焊接角钢构件不需要考虑局部稳定折减;作为铁塔主材使用时可按电力行业规范中b类截面考虑。

For ultra-high voltage(UHV) transmission towers,welded large angles can solve the difficulties in purchasing hot-rolled large angles. Although welded large angles have been applied in UHV transmission towers,there is little research on residual stress distribution and stability bearing capacity of such members. In this situation, the temperature field and stress field of Q420 plates were calculated based on the processing technique of welded angles after welding,and the residual stress distribution of the cross sation was obtained. A series of models with limb width of L250,280,L 300,L 329,L 360,were built considering initial imperfection and residual stress,and the stability bearing capacity of angles member welded Q420 thick plates was discussed and analyzed according to finite element calculation. The results showed that the residual tensile stress was beyond yield strength fyand the max compressive stress was about 0. 3 f_y(f_y represenes the yield strength of steel),local buckling had little effect on bearing capacity in this kind of section,column curve of section type b was suitable for angle tower chord members in power industry specification.