航空機エンジンディスクボルトホールの渦流探傷検査条件の最適化

－解析方法の探究－

抄録

Aircraft engine disks are critical rotating parts and flaw detection by non-destructive inspection is essential. Since surface defects in particular can be the origin of fracture, eddy current inspection is carried out. This paper seeks robust inspection conditions that increase the S/N ratio (ratio of the defect signal component to the irregular signal component caused by surface conditions that hamper detection of the defect signal) and examines the analytical methods for setting the conditions. Although the gain was reproduced in a zero point proportional analysis of the defective area and S/N ratio, in the factor effect diagram of the S/N ratio there was considerable ripple and slope in the error column. To remedy this problem, the defect and irregular signals were analyzed independently and the defect signal was analyzed using a reference point proportional expression with a zero-point adjustment made according to the irregular signals component. As a result, detection capability was improved in a direction that reduced the irregular signal component, and under the optimal conditions,it was possible to detect minute flaws that had been difficult to detect with the conventional flaw detection conditions.