焊管内裂纹电磁激励红外无损检测数值模拟

Numerical simulation of electromagnetic exciting infrared NDT of internal crack in welding pipe

研究ANSYS有限元模拟下基于电磁激励红外热像的直缝焊管内部裂纹检测,为实践提供有价值的参考依据。根据感应加热原理,建立了电磁场和温度场的数学模型,进行两个场的顺序耦合分析,通过改变裂纹埋藏深度、线圈位置、材料物性、感应加热时间,探讨其对内部裂纹可检测规律的影响。仿真结果表明,内部裂纹的存在影响试件表面的温度场,并且随着埋藏深度的增加以及线圈位置偏离越远,表面获得的温度也随之下降,铁磁性材料更容易被检测出来,通过选择合适激励频率或电流强度、线圈位置,红外热像仪能够探测到内部裂纹的存在。

To provide valuable references for practice, a finite element analysis software ANSYS is used to simulate non-destructive testing（NDT） of internal crack in straight seam welding pipe by electromagnetic exciting infrared ther- mography. The mathematical model of electromagnetic field and temperature field is built according to the induction heating principle. The order coupling analysis of two fields is conducted, and the influence of internal crack of welding pipe on detection law are discussed through changing the buried depth, coil position, materials and induction heating time. The results indicate that internal crack influences the temperature of specimen surface, and the surface tempera- ture decreases with increase of the buried depth and coil eccentric distance. Besides, the ferromagnetic material is more likely to be detected. The existence of internal cracks can be detected by selecting the appropriate excitation fre- quency or current intensity and the coil position.