| Download | - View final version: B707 lap joint specimen No. 349 - NDI inspections (PDF, 4.6 MiB)
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| DOI | Resolve DOI: https://doi.org/10.4224/40002729 |
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| Author | Search for: Taremi, F.1; Search for: Bellinger, N.1; Search for: Brothers, M.1; Search for: Gould, R.1 |
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| Affiliation | - National Research Council of Canada. NRC Institute for Aerospace Research
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| Format | Text, Technical Report |
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| Physical description | 39 p. |
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| Subject | non-destructive inspection; cracks; pillowing corrosion; teardown; thickness loss; X-ray; eddy current; pulsed eddy current; ultrasonic |
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| Abstract | Three lap joint sections taken from a B707 aircraft were initially inspected using x-ray inspection techniques to determine if corrosion pillowing cracks were present. Since numerous pillowing cracks were found in all three lap joints, four other nondestructive inspection (NDI) techniques were used to characterize the damage present in each joint. A visual inspection was first made to assess the damage present on the outer surfaces of each joint (both inboard and outboard skins). The NDI techniques that were used included multi frequency eddy current, pulsed eddy current, ultrasonic (C Scan) and D Sight™ inspections. The level of corrosion and corrosion pillowing that was present in these specimens was sufficient to cause a number of the rivet heads to “fail”. Some of the rivets had been replaced, probably during prior maintenance but had since failed due to the stress caused by the corrosion pillowing. There was also corrosion present on the inboard surface as well as on the stringers. The paint had not been stripped and there were no surface cracks visually apparent. The three specimens were separately inspected and all the results obtained are shown in the figures presented below. The eddy current inspections were carried out using four different frequencies 1.1 kHz, 2.4 kHz, 4.3 kHz and 9.6 kHz. Ultrasonic inspection was performed at a frequency of 15 MHz. The X-ray inspection displayed several cracks around the majority of the rivets. High beam energy levels were required to detect pillowing cracks in the intact joint and resulted in extremely dark images thus only one X-ray image, from 349B, is shown in this report. From all of the x-ray inspections the areas indicated to have significant pillowing cracks are noted on the schematic of each specimen. |
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| Publication date | 2003-09-25 |
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| Publisher | National Research Council of Canada |
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| Series | |
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| Language | English |
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| Peer reviewed | No |
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| NPARC number | 8928897 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 86a78733-0669-4025-9956-b9979bd2d5b2 |
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| Record created | 2009-04-23 |
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| Record modified | 2022-10-19 |
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