一种考虑力学因素的钢结构腐蚀疲劳寿命评估方法

AN ASSESSMENT METHOD FOR CORROSION FATIGUE LIFE OF STEEL STRUCTURE CONSIDERING MECHANICAL FACTORS

腐蚀环境下服役的钢结构经常承受腐蚀与疲劳的双重破坏,提出一种考虑循环荷载与腐蚀破坏耦合作用的新方法以评估钢结构腐蚀疲劳寿命。利用一种基于力学因素的钢结构腐蚀数学模型,确定钢结构在循环荷载作用下不同时间点的腐蚀深度,分别建立精确有限元模型计算结构损伤,最后结合Miner准则确定累计损伤,评估疲劳寿命。与传统方法相比较,该方法考虑了腐蚀与疲劳的耦合效应,计算所得的腐蚀速度更快、腐蚀疲劳寿命更低。腐蚀疲劳对结构损伤较传统认识更大,应予以足够重视。该方法操作简便,实用性强,可用于评估一般钢结构的腐蚀疲劳寿命。

Steel structures in corrosive environment often endure coupling damage from corrosion and fatigue.This paper proposed a new assessment method for corrosion fatigue life of steel structure,including the coupling effect of cyclic loading and corrosion damage.Defining the corrosion depth of steel structure under cyclic loading on different time through a corrosion mathematical model based on mechanical factors.Accurate finite element models were established to calculate the structure damage.Finally,the cumulative damage was obtained by Miner guidelines,and the fatigue life was also evaluated.Comparing with traditional methods,the coupling effect of corrosion and fatigue were taken into account to new method.The results showed that the calculated corrosion rate from new method was faster,and the corrosion fatigue life was shorter.It should be paid more attention that corrosion fatigue could cause more damage to structure than people thought.Furthermore,this method is convenient and practical to assess the corrosion fatigue life of normal steel structure.