基于可靠性理论的桅杆焊缝风振疲劳分析

Wind-induced Fatigue Analysis of Welded Seam ofGuyed-mast Based on Reliability Theory

根据某一地区风荷载的分布规律 ,得到不同方向不同风速的累积时间 ,模拟风压脉动时程曲线 ;建立桅杆结构的空间有限元模型 ,计算结构在风荷载作用下的响应 ;得到不同方向不同风速作用下纤绳节点板焊缝的应力循环次数和应力幅 ;根据Miner线性累积损伤准则 ,得到总应力循环次数和等效应力 ;以节点焊缝的极限疲劳循环次数作为随机变量 ,基于可靠性理论 ,计算得到不同服役期节点焊缝的疲劳可靠性 .

According to the distribution of wind load at a certain area,the cumulative time of wind load at different velocities and in different directions is obtained,and the time-history curves of the pulsative wind load are simulated in this paper.The spacial model of a guyed-mast is set up in this paper and the wind-induced dynamic response is computed.The stress ranges and the corresponding cycle numbers under different wind loads of the welded seam connecting the mast and the joint plate are calculated.Based on the Miner linear cumulative damage theory,gross number of the stress cycles and the equivalent stress are derived.Taking the critical fatigue cycle number of the welded seam as a stochastic variable,the fatigue reliability of the welded seam under different service time is computed based on the reliability theory.