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Modal Test Technology as Non-Destructive Evaluation of Space Shuttle StructuresModal test and analysis Is being used for nondestructive evaluation of Space Shuttle structures. The purpose of modal testing is to measure the dynamic characteristics of a structure to extract its resonance frequencies, damping, and mode shapes. These characteristics are later compared to subsequently acquired characteristics. Changes in the modal characteristics indicate damage in the structure. Use of modal test technology as a damage detection tool was developed at JSC during the Shuttle acoustic certification program and subsequent test programs. The Shuttle Modal Inspection System was created in order to inspect areas that are impossible or impractical to inspect with conventional methods. Areas on which this technique has been applied include control surfaces, which are covered with thermal protection tiles, and the Forward Reaction Control Module, which is a frame structure that supports various tanks, thrusters, and fluid lines, which requires major disassembly to inspect. This paper traces the development of the technology, gives a status of its implementation on the Shuttle, explains challenges involved in implementing this type of inspection program, and suggests future improvements in data analysis and interpretation. Dual-use applications of the technology include inspections of bridges, oil-platforms, and aircraft.
Document ID
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Grygler, Micheal S.
(NASA Johnson Space Center Houston, TX United States)
Date Acquired
August 17, 2013
Publication Date
May 1, 1994
Publication Information
Publication: Dual-Use Space Technology Transfer Conference and Exhibition
Volume: 1
Subject Category
Quality Assurance And Reliability
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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