含不同深度球形缺陷钢管应力集中系数的有限元分析

Finite Element Analysis of the Stress Concentration Factor of Sphere Defect in Various Depths on Pipeline

通过有限元方法模拟了含单个不同深度(即缺陷深度和半径均分别为t/8,t/4和t/2,其中t为钢管公称壁厚)球形腐蚀缺陷X70钢管在不同服役条件(内压力)下的应力和应变状态,得出不同状态下最大等效应力和最大等效应变分布情况,进而求得含缺陷钢管缺陷应力集中系数。结果表明:在静载条件下,缺陷深度为t/8,t/4和t/2时其对应的应力集中系数分别为2.52,3.43和7.16,并由此得出了球形缺陷应力集中系数与缺陷深度关系的拟合公式,相关系数为0.994;采用有限元方法求解球形缺陷管道应力集中系数与文献中同类缺陷钢管的结果一致,证明了有限元方法的正确性。

The stress and strain situations of the X70 pipeline With single spnec different in depth （ both the defect depths and the defect radii were t/8, t/4 and t/2 respectively, t is pipe wall thickness） were analyzed by finite element method （FEM） under different service conditions （inner pressures） . The Von Mises equivalent stress distribution and the Von Mises equivalent strain distribution at different conditions were obtained. And the stress concentration factor was calculated according to the FEM results. The results showed that in dead loading the stress concentration factor of corroded pipe with defect depth of t/8, t/4 and t/2 were 2.52,3. 43 and 7.16, respectively. Meanwhile the fitted equation of stress concentration factor and ratio of defect depth was established, and the correlation coefficient was 0. 994. Besides, the results of stress concentration factor based on the FEM coincided with the results of similar references, which proved the correctness of the FEM.