Multi-Frequency Eddy Current Nondestructive Evaluation of Aerospace Structures

摘要

Aging aircraft structures are prone to corrosion, which weaken the damage tolerance capability and accelerate the growth of cracks within the structures. To investigate these cracks and to validate repairs, corrosion quantification techniques are considered important. The objective of this research is to perform multi frequency eddy current aerospace nondestructive evaluation (NDE) on aerospace structures to determine their structural integrity. Damage detection and computation of flaw dimensions based on multi frequency eddy testing is a typical Nondestructive Testing (NDT) inverse problem. Advanced adaptive thresholding algorithm is developed to process the actual NDT data acquired from NDT facilities of Pakistan International Airlines (PIA). Eddy Testing data acquired at different frequencies contain complementary information. Therefore, modern data fusion technique is incorporated in diagnostic algorithms to improve the accuracy of the solution. The proposed fusion algorithm reduces the number false calls and results in relatively small number of regions that need to be analyzed by the classification algorithm. The major conclusion of the project is improvement in aerospace NDT infrastructure in Pakistan. In-house knowledge would also facilitate the decision makers to decide flight worthiness of the air crafts in short period of time.