钛合金深层裂纹缺陷涡流检测仿真与实验研究

Simulation and Experimental Research on the Deep Crack Defects of Titanium Alloy with Eddy Current Testing

针对常规涡流只能检测金属构件近表面缺陷的瓶颈,本文基于TMR隧道磁阻阵列设计了多通道差分激励涡流检测探头,实现了对钛合金板件深层裂纹缺陷的检测。通过模拟优化了线圈参数,设计了差分式矩形激励线圈组合结构,从而提高TMR阵列对缺陷的检测效果,并制作了TMR阵列的差分涡流检测探头。分别针对钛合金板件表面3 mm和4 mm下的深层裂纹缺陷进行实验测试,表面3 mm下的长度为12 mm、6 mm、3 mm微裂纹检测得的感应磁场强度分别为0.01992 mT、0.0152 mT、0.00528 mT;表面4 mm下的6 mm长微裂纹的感应磁场强度大约为0.00448 mT。结果表明,所设计的TMR阵列涡流探头对缺陷长度变化相较于宽度变化更为敏感,能有效检测出深层微小裂纹缺陷。

Aiming at the problem that conventional eddy current can only detect near-surface defects of metal components,this paper presents a multi-channel differential excitation eddy current probe based on the tunnel magnetoresistance(TMR)sensor array to realize the detection of deep cracks in titanium alloy plates.The coil parameters are optimized by simulation.The differential rectangular excitation coils are designed to improve the defect detection effect of TMR array,and the differential eddy current probe is fabricated.The defects under 3 mm and 4 mm on the surface of the titanium alloy plate are detected.The induced magnetic field intensity of the 12 mm,6 mm and 3 mm microcracks under 3 mm of are 0.01992 m T,0.0152 m T and 0.00528 m T.The induced magnetic field intensity of the 6 mm microcrack under 4 mm is 0.00448 m T.The results show that the TMR array eddy current probe is more sensitive to the change of defect length than the change of width.The probe can detect the deep microcracks effectively.