Frequency Optimization of Eddy Current Testing for Surface Flaw Detection in Aluminum and Stainless-Steel Aerospace Components

Abstract

Fatigue in aircraft components has caused numerous issues and accidents, manifesting at different phases of flight. This study evaluates the effectiveness of Eddy Current Testing (ECT) as a non-destructive testing (NDT) method for identifying surface and near-surface defects in aerospace components, specifically aluminum and stainless steel. Using the Olympus Nortec 600 with a pencil probe operating at 100kHz – 500kHz, the research assesses ECT's sensitivity, penetration depth, and overall efficiency. A significant focus is on inspecting components without removing protective coatings, thereby reducing maintenance time and preserving material integrity. The results were recorded and collected for consistently 5 days, to compare which frequency results are recorded the best and to ensure the readings are done right in between those days. By comparing ECT results on calibration blocks and actual aircraft parts, the study measures the method's accuracy in detecting flaws such as cracks, pores, and corrosion pits. The analysis also considers the impact of environmental factors on ECT performance and explores strategies to enhance its application on modern composite materials and advanced alloys. With the concluded results, aluminum’s high conductivity and lower density make 400kHz optimal, while stainless steel’s lower conductivity and higher density make 500kHz more effective. Key findings indicate that ECT provides rapid and efficient inspections, capable of detecting defects through coatings without extensive surface preparation, thus proving practical for operational settings. The research highlights ECT's strengths and limitations, recommending its integration into routine maintenance protocols to improve safety, reduce downtime, and achieve cost savings.