碳纤维复合材料热损伤涡流检测技术研究

利用涡流检测技术对碳纤维复合材料热损伤进行检测。分别在1.00、2.00、3.33、5.00 MHz检测频率下,对3个热损伤程度不同的损伤点进行检测,采集各频率下的检测线圈归一化阻抗曲线,并对其进行X、Y方向的分解,利用信号幅值变化识别热损伤区域,最后采用水浸超声C扫描检测方式对涡流检测结果进行验证。结果表明:热损伤程度及热损伤面积大小对涡流阻抗显示有明显影响,热损伤程度越严重,曲线幅值变化越大;热损伤面积越大,曲线越宽;频率变化改变了阻抗曲线的相位,但对检测效果的影响不明显。所测出的热损伤区域虽有误差,但与水浸超声C扫描检测结果接近。该研究对碳纤维复合材料热损伤评估具有参考价值。

Research on Eddy Current Testing Technology for Thermal Damage of Carbon Fiber Composites

Eddy current testing technology was used to detect the thermal damage of carbon fiber composites. Three damage points with different degrees of thermal damage were tested and compared at 1.00, 2.00, 3.33 and 5.00 MHz detection frequencies, respectively. The normalized impedance curve of the detection coil at each frequence was collected and decomposed in X and Y directions. The thermal damage area was identified with the change of signal amplitude. Furthermore, the eddy current testing results were verified by immersion ultrasonic C-scan testing. The results show that the degree and area of thermal damage have obvious effects on impedance in eddy current testing. The more serious the thermal damage, the greater the change of the impedance curve amplitude. Furthermore, the larger the thermal damage area, the wider the curve. The frequency variation changes the phase of impedance curve, but has little effect on the detection sensitivity. Although there are errors in the measured results of heat loss area, they are close to those from immersion ultrasonic C-scan testing. This work is of reference value for conducting thermal damage assessment of carbon fiber composites.