外穿式集中绕组激励旋转电磁场涡流无损检测系统

Encircling rotating field eddy current non-destructive evaluation system with concentrated excitation windings

本文提出带集中式绕组可方便开合的新型探头设计,实现基于旋转电磁场涡流原理的管件外检测。通过COMSOL有限元模型研究了集中式绕组产生的旋转磁场特征及接收线圈参数对检测效果的影响,仿真结果表明集中式绕组可产生适于管件外壁缺陷检测的旋转电磁场,匝数较多、紧贴管道外壁并位于激励线圈端部的圆形线圈可更好地实现畸变信号拾取。构建了外穿式集中绕组激励旋转电磁场涡流无损检测系统,实现了对0.5 mm宽的周向与轴向裂纹检测,测试了系统对不同深度裂纹的识别能力,并利用位于管道外壁0到90°不同位置的裂纹验证了检测系统对裂纹周向定位能力,结果表明研发系统可进行任意方向裂纹的检测和周向定位,为连续管等管状构件的外检测提供一种新的方法。

This article proposes a new probe design with concentrated windings that can be easily opened and closed.The external inspection of pipes is realized,which is based on the principle of rotating electromagnetic field eddy current.Through the finite element(FE)model constructed in COMSOL,the characteristics of the rotating magnetic field generated by the concentrated winding and the influence of various parameters of the receiving coil on the detection effect are studied.Simulation results show that the concentrated winding can generate a rotating electromagnetic field that can be used to achieve defect detection on the outer wall of the pipeline.The pick-up of the distorted signal can be realized in a better way by utilizing the circular coil which has many turns and is close to the outer wall of the pipe and at the end of the excitation coil.An encircling rotating field eddy current(RoFEC)non-destructive evaluation system with concentrated excitation windings is established to achieve the detection of 0.5 mm wide circumferential and axial cracks.The ability of the system for identifying cracks at different depths is tested.Cracks located at different positions on the outer wall of the pipeline from 0 to 90°are used to verify the ability of the detection system to determine the circumferential location of the defect.Results show that the developed system can detect crack of arbitrary direction and locate its circumferential location,which provides a new approach for the external detection of tubular components such as coiled tubes.