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Proceedings Paper

Probabilistic nondestructive evaluation of bonded aluminum honeycomb structures
Author(s): Lloyd A. Schaefer
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Paper Abstract

Aluminum honeycomb panels fabricated in accordance with spacecraft fracture control guidelines must be evaluated to a 90/95 POD/CL (probability of detection/confidence) level for detection of the critical initial flaw (CIF) size. Severe weight limitations can drive the CIF to a size of one cell diameter, or smaller. Additionally, producibility (low or no type II errors) must be maintained, and inspection costs minimized. To assure these goals, a reliability demonstration program was undertaken on thin skin panels for the Space Station Electric Power System ORU (orbital replacement unit) enclosures. This paper examines the probabilistic NDE process in detail, including: analysis of the manufacturing methodology, expected flaw types, construction of the disbond flaw data base, and the subsequent evaluations and results using laser shearography. The experimental data is then reduced utilizing the statistical methodology outlined in a proposed military standard for NDE reliability demonstrations, and contrasted against conventional through transmission ultrasonic inspection. The effort revealed that substantial gains in system reliability and flaw type discrimination are possible with laser shearography, along with a nearly order of magnitude reduction in inspection time.

Paper Details

Date Published: 7 July 1995
PDF: 12 pages
Proc. SPIE 2455, Nondestructive Evaluation of Aging Aircraft, Airports, Aerospace Hardware, and Materials, (7 July 1995); doi: 10.1117/12.213537
Show Author Affiliations
Lloyd A. Schaefer, Rockwell International Corp./Rocketdyne Div. (United States)

Published in SPIE Proceedings Vol. 2455:
Nondestructive Evaluation of Aging Aircraft, Airports, Aerospace Hardware, and Materials
Tobey M. Cordell; Raymond D. Rempt, Editor(s)

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