含腐蚀凹坑缺陷管道的极限载荷研究

腐蚀凹坑是石油与天然气输送及石化管道常见的缺陷之一 ,会使管道产生应力集中 ,抗疲劳载荷能力降低。为寻求腐蚀球形凹坑对压力管道极限载荷的影响 ,用有限元弹塑性分析法和试验方法 ,对含腐蚀球形凹坑缺陷的压力管道进行研究 ,得到了含不同球形腐蚀凹坑缺陷压力管道在内压和弯矩联合作用下的极限载荷。试验研究证明 ,在内压和外弯矩作用下 ,腐蚀球形凹坑底部应变值最大 ,并首先屈服 ,试验测定载荷 -应变曲线与有限元计算的基本一致 ,最大误差为 7 3 2 %。腐蚀凹坑半径相同时 ,管道的极限载荷随凹坑深度的增加而降低 ;而凹坑深度相同时 ,极限载荷随凹坑半径的加大而降低。

A study on the limit load of pipeline with corrosion pit

Corrosion pits, one of the common defects of oil and gas pipelines, cause stress concentration in the lines and reduce the resistance to fatigue load. To make clear the influence of spherical corrosion pits on pressure lines, an inves tigation is conducted on the lines with finite element analysis and test. The te st is made on the pressure line with various spherical corrosive pits under the action of both internal pressure and bending moment, and the limit load of the l ine is obtained. The investigation and test show that, under the action of inter mal pressure and outer bending moment, the bottom of the corrosion pit takes the maximum strain and is yielded first, and the load-strain curve is close to the result of the finite element calculation, with a maximum error of 7 32%.