基于超声波检测的管道内缺陷剩余强度研究

Research on Remaining Strength in Internal Defects of Pipeline Based on Ultrasonic Detecting Method

利用超声波检测装置对管道内壁的标准缺陷进行检测,将检测结果与标准缺陷的尺寸数据进行对比分析。建立管道内缺陷的三维模型,采用有限元软件ANSYS对其失效压力和等效应力进行研究,分析不同尺寸的缺陷对管道失效压力的影响;同时利用ASME B31G评价准则对缺陷数据进行分析,获得腐蚀缺陷的失效压力和剩余强度。结果表明:超声波检测技术在管道内腐蚀缺陷检测具有可行性与可靠性;当缺陷深度为壁厚的65%以上时,随着缺陷长度的增加,非线性随机有限元预测结果与ASME B31G分析结果比较接近;当缺陷深度约为壁厚的35%时,随着缺陷长度的增加,两者结果相差较大。

The normal defects of inner pipeline were detected by Ultrasonic Testing,the testing results were compared with dimensional data of normal defects;3Ddefective models of pipeline had been built by using finite element software of ANSYS to study failure and equivalent stress of different sizes,the influence of failure pressure with different size of defects were also analyzed.Meanwhile,ASME B31G—2009was used to analyze defective data and count failure stress and remaining strength of corrosion defects.These results indicate that ultrasonic detecting has both feasibility and reliability in detecting internal corrosion defects of pipeline by results.When the defective depth exceeds 65% of the wall thickness and the defective length increases,the predicted results of nonlinear stochastic finite element are comparatively consistent with that of the ASME B31 G.However,when the defective depth comes close to 35%,the discrepancies are adequately large with the increase of defective length.