Multi-Frequency Eddy Current Nondestructive Evaluation of Aerospace Structures

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.

1. Nondestructive Testing Handbook, second edition: Volume 10, Overview. Columbus, OH: American Society for Non Destructive Testing (1996). 2. Non Destructive Testing Methods, TO33B-1-1 (NAVAIR 01-1A-16) TM43-0103. Washington DC: Department of Defense (June 1984). 3. R.C. McMaster S.A.W., “A Basic Guide for Management Choice of non Destructive Test,” in Symposium on the role of Non Destructive Material Testing in the Economics of Production. A. International, Editor. 1951: West Conshohocken. 4. Saxby, S.M., “Magnetic Testing of Iron,” Engineering, 1886. 5: p. 279. 5. Forster, F., “The First Picture: A Review of the initial steps in the development of Eight Branches of Non Destructive Material Testing,” Materials Evaluation, 1983. 41(3): p. 1477-1488. 6. Burrows, C.W., Apparatus for Testing Magnetizable Objects, 1928: United States. 7. Libby, H.L., Introduction to Electromagnetic Nondestructive Test Methods, 1971, New York: John Wiley and Sons. 8. Khan, T. and P. Ramuhali, “Particle filterbased multi-sensor fusion for solving low frequency electromagnetic NDE inverse problems,” IEEE Trans. Of Measurement and Instrumentation ,Vol: 60 No:6, June 2011, pp. 2142-2153. 9. Yang, G., T. Khan, L. Udpa, S. Udpa and J. Kim, “Pre-processing methods for eddy current data analysis using Hilbert- Huang Transform,” to be presented at 15th international symposium on electromagnetic and mechanics, Italy, Sept 2011. 10. Forsyth, D.S. et al, “The role of data fusion in NDE for aging aircraft,” Proc, SPIE, vol. 3394, (2000) pp.47-58.
Usage Shares
Total Views
40 Page Views
Total Shares
0 Tweets
0 PDF Downloads
0 Facebook Shares
Total Usage