基于模态分离算法的管道焊缝缺陷模拟

在温度、压力、介质腐蚀、振动等影响下，在役工业管道焊缝内部的小缺陷易发展成裂纹，对管道安全运行产生危害。在模态对称分离算法检测单焊缝管道缺陷的基础上，基于L（0，2）模态导波进行数值模拟，分别以前焊缝缺陷对称面、弯管对称面为纵坐标建立新的笛卡尔直角坐标系，根据对称原理，易于提取缺陷特征。模拟结果表明，非对称幅值与裂纹深度呈指数函数关系，该方法可以实现双焊缝和弯管焊缝缺陷的识别和定量。

Simulation for Weld Defects in Pipe Based on Modal Separation Algorithm

With the influence of temperature,pressure,medium corrosion and vibration,small defects in the weld can be grown into cracks,which will do harm to the in-service industrial pipelines.Based on the modal symmetry algorithm of defect detection of single weld pipeline,the simulation of modal guided waves in L (0,2) is carried out.According to the symmetry principle,it''s easy to extract the defect features.A new Cartesian coordinate is established by using the symmetry surface of the weld defects and weld elbow as the vertical axis respectively.The simulation results show that the asymmetric amplitude is in exponential function with the crack depth,and the method can realize the identification and quantification of defects in double welds and elbows.