腐蚀凹坑干涉效应与疲劳寿命计算

为了寻求由于腐蚀凹坑尺寸差异引起的干涉效应对凹坑周围应力的影响和预测腐蚀疲劳寿命，采用ANSYS分析和计算不同中心距和深度的腐蚀凹坑在内压作用下的应力分布规律及其疲劳寿命。结果表明：最大应力值随着凹坑深度而增加，但疲劳循环次数却下降，当凹坑深度与器壁厚度大于1/3时其最大应力增长幅度较大；当两凹坑在相切且凹坑深度大于4 mm时干涉效应最显著，应力集中现象更为严重，其疲劳循环次数急剧减少；当相邻两凹坑不相交时干涉效应不明显，相邻两凹坑的最大应力分布及疲劳循环次数均与单凹坑时相近，即两凹坑之间几乎无影响。

Interference Effect and Fatigue Life Calculation of Corrosion Pits

In order to find out the influence of the interference effect caused by the difference of corrosion pit size on the stress around the pit and predict the corrosion fatigue life. Analyze and calculate the stress distribution and fatigue life of corrosion pit with different center distance and depth under internal pressure load based on ANSYS. The results show that the maximum stress increases with the pit depth, but the number of fatigue cycles decreases. The maximum stress increases greatly when the pits depth and the wall thickness more than 1/3. The interference effect significant when the two pits are tangent and the pit depth is more than 4mm, the stress concentration is more serious and the number of fatigue cycles is sharply reduced. When the two adjacent pits do not intersect the interference effect is not obvious. The stress distribution and fatigue cycle times of two pits adjacent are similar to those of single pit that is there is almost no influence between the two pits.