skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

Abstract

Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.

Authors:
;  [1]
  1. Nondestructive Evaluation and Structural Health Monitoring Laboratory, Department of Mechanical and Aerospace Engineering, University of Missouri - Rolla, 1870 Miner Circle, Rolla, MO 65409-0050 (United States)
Publication Date:
OSTI Identifier:
21054941
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 894; Journal Issue: 1; Conference: Conference on review of progress in quantitative nondestructive evaluation, Portland, OR (United States), 30 Jul - 4 Aug 2006; Other Information: DOI: 10.1063/1.2718112; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AGING; ALUMINIUM; ALUMINIUM ALLOYS; CORROSION; CORROSION PRODUCTS; CRACKS; DEFECTS; DETECTION; EDDY CURRENT TESTING; EDDY CURRENTS; FAILURES; FATIGUE; JOINTS; MONITORING

Citation Formats

Okafor, A. C., and Natarajan, S.. Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life. United States: N. p., 2007. Web. doi:10.1063/1.2718112.
Okafor, A. C., & Natarajan, S.. Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life. United States. doi:10.1063/1.2718112.
Okafor, A. C., and Natarajan, S.. Wed . "Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life". United States. doi:10.1063/1.2718112.
@article{osti_21054941,
title = {Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life},
author = {Okafor, A. C. and Natarajan, S.},
abstractNote = {Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.},
doi = {10.1063/1.2718112},
journal = {AIP Conference Proceedings},
number = 1,
volume = 894,
place = {United States},
year = {Wed Mar 21 00:00:00 EDT 2007},
month = {Wed Mar 21 00:00:00 EDT 2007}
}
  • Cracks occurring on commercial aircraft fuselage lap joints made of aluminum alloys often caused by scribe lines made during the removal of process of moisture sealing materials between two layers. These cracks on thinner bottom skin layers can be obscured by thicker top plates with paint. A portable GMR (Giant Magnetoresistive) sensor based eddy current system has been developed and tested on several simulated aircraft lap joints samples with EDM notches. Various thicknesses of layers are used to simulate the test as used on different combinations of lap joints. Length and depth of cracks are important factors for the safetymore » of aircraft. Test results are used to come up with a portable nondestructive inspection system which is easy and fast with a high reliability of detecting cracks longer than a half inch in length and 0.010 inches in depth.« less
  • In bolted or riveted joints where the interfacial pressure is not uniform, the total resistance to heat flow in a vacuum is the result of two separate components: the microscopic resistance, which arises due to the constraint of the heat flow through the actual microscopic contact spots, and the macroscopic resistance, which exists because the contact zone, over which these microscopic contact spots are located, is only a fraction of the total interfacial area. Presented is a review of the recent literature addressing the interfacial pressure distribution and the size of the contact zone, in so far as they affectmore » the heat transfer at these interfaces. A survey of the experimental work on contact pressure and the associated heat transfer in bolted joints is presented, along with the size of the actual contact zone which was identified as an important parameter affecting both the microscopic and the macroscopic resistances. An analysis is performed in which it is formally shown that the exact form of the stress distribution within the contact zone is immaterial for the computation of the total microscopic conductance if the available theoretical results for local solid spot conductance are used.« less
  • A short study has been conducted to assess the performance of friction stir welded Mg/steel joints under dynamic loads. The major mode of failure was found to be top Mg sheet fracture. Crack initiation is noted to have taken place at the Mg/steel interface. The fatigue life of the joints is found to be significantly different than the fatigue data of the Mg alloy obtained from the literature. The reasons behind such a difference have been examined in this work.