考虑焊接残余应力的桅杆结构拉耳节点风致疲劳裂纹萌生寿命评定

Assessment of wind-induced fatigue crack initiation life at guyed mast earplate joints considering welding residual stresses

提出对评定桅杆结构拉耳节点焊缝处的裂纹萌生累积疲劳损伤程度的方法。在建立桅杆结构拉耳节点风致应力场的多尺度分析方法的基础上,考虑拉耳节点的焊接残余应力,用基于临界面法的应变疲劳分析方法进行在焊接残余应力和纤绳外荷载双重作用下的累积疲劳损伤量的计算,然后依据Mason-coffin公式及Miner疲劳累积损伤准则估算桅杆结构纤绳连接拉耳各不同风向不同平均风速作用下的多轴疲劳累积损伤,由总损伤计算出裂纹萌生寿命。

A new method for assessing the degree of the cumulative fatigue crack initiation damage of the welds of earplate joints of a guyed mast,which connect the mast with the cable,is proposed.Based on the multi-scale wind-induced stress analysis of the earplate joint,and considering the welding residual stresses at the earplate joints,the critical plane approach is used for the calculation of the cumulative strain fatigue damage due to combined actions of the welding residual stresses and wind load.The multi-axis fatigue accumulative damages of the welds of earplate joints in different wind orientations and at different wind average velocities are then evaluated on basis of Mason-coffin formula and Miner fatigue accumulative damage rule.The crack germination life is also calculated from the total damage.