线圈弯曲角度对柔性涡流传感器缺陷检测能力的影响

Influence of coil bending angle on the defect detection ability of flexible eddy current sensor

采用有限元仿真和实验方法分析了圆形线圈处于不同弯曲角度时,柔性涡流传感器对模拟裂纹缺陷方向角及深度的检测能力变化规律。结果表明:圆形线圈弯曲导致各向均匀涡流场朝单向涡流场转变,无论是工作于自感还是互感检测模式下,柔性涡流传感器对不同方向裂纹缺陷的检测灵敏度均降低。对于90°裂纹,当线圈弯曲角度为30°时,自感和互感模式的检测灵敏度分别下降约7%和45%。线圈弯曲导致传感器对裂纹方向、深度的识别能力随线圈弯曲角度增大而单调下降。相比自感模式,互感模式下柔性涡流传感器对裂纹方向及深度的识别能力更佳。线圈与曲面贴合造成的弯曲对传感器性能的影响不可忽略,在设计柔性涡流传感器时应合理选择弯曲角度范围。

Finite element simulation and experiment methods are employed to analyze the detection ability of flexible eddy current sensor for detecting the orientation angle and depth of a simulated crack defect when the circular coil is in different bending angles.The obtained results show that the bending of the circular coil leads the isotropic eddy current field to change to unidirectional eddy current field.No matter the flexible eddy current sensor works under self-induction mode or mutual-induction mode,the sensitivity of the flexible eddy current sensor to the crack faults with different orientation angles decreases.For instance,when the bending angle of the coil is 30°,the sensitivity of the flexible eddy current sensor to the crack with an orientation angle of 90°in self-and mutual induction modes reduces by 7%and 45%,respectively.In addition,the coil bending causes that the recognition ability of the flexible eddy current sensor to the crack orientation angle and depth monotonously decreases as the bending angle of the coil increases.Under mutual-induction mode the flexible eddy current sensor achieves better recognition ability to crack orientation angle and depth compared with the case under the self-induction mode.The influence of the coil bending occurred in the shape matching between the coil and curved surface on the performance of the sensor can not be ignored.A reasonable coil bending angle range should be selected when designing the flexible eddy current sensor.