基于超声导波检测的弯管缺陷数值模拟研究

The Numerical Simulation Research for the Bend Tube Defects Detection Based on Ultrasonic Guided Wave

针对弯管缺陷检测的问题,利用有限元方法,对弯管缺陷超声导波检测进行数值模拟。通过建立90°弯管模型,在弯管中设置不同尺寸以及不同距离的双缺陷,根据超声导波理论设置有限元计算的参数,由计算结果拟合出双缺陷中直管段腐蚀坑缺陷尺寸变化对弯头处裂纹缺陷反射系数的影响曲线以及缺陷间距离不同时反射系数的变化趋势曲线。结果表明,当弯头处缺陷的尺寸不变时,其反射系数随直管段缺陷尺寸的变大而减小,两个缺陷间的反射系数与两缺陷间的距离变化关系可忽略不计。研究结果对弯管缺陷程度检测有一定应用价值。

For the problem of bend tube defects detection,did some numerical simulation research for the bend tube defects detection based on ultrasonic guided wave testing by using finite element method. First of all,this paper built a 90 degrees bend model,and set double defects like different sizes and different distances in the bend model. Secondly,set the parameters of finite element calculation based on the ultrasonic guided wave theory. Then,according to the calculation results,made a fitting curve of the influence of corrosion pit defect dimensional change in straight pipe to crack curve reflection coefficient in elbow,and the variation tendency curve of the reflection coefficient with the change of the distances between defects is made as well. The results show that when the size of the elbow defects remains constant,the reflection coefficient decreases with the straight pipe flaw size increasing,and the changing relationship between the reflection coefficient and the distance of the two defects can be ignored. These results have an application value for the bend tube degree of defects detection.