Supervoltage NDE Techniques for Large Aerospace Structures.
Abstract
Innovative technical approaches for detecting and characterizing defects in aerospace structures like large solid rocket boosters or jet engines are urgently needed. Unfortunately, in fully assembled components, zones which are the most critical to system reliability are often the most inaccessible to standard examination techniques. A computed tomography (CT) system can provide excellent images of otherwise inaccessible areas but the size and opacity of large aerospace components preclude the use of even the most energetic industrial CT systems produced to date with power extended for the largest solid rocket boosters to peak energies in the 40- to 60-MV range. The use of these supervoltage energies for CT completes the logical extension since material attenuations begin to increase for higher energies. A Phase I effort verified the feasibility of the concept by resolving key questions relating to operation at supervoltage energies. The key objective of the Phase II program was to obtain a supervoltage CT image of an aerospace structure which, because of its size and opacity, could not be imaged with current CT technology. Supervoltage CT images of many configurations of a simulated 3.9-m-diameter, 12-mm steel case solid rocket booster, obtained on a pre-prototype supervoltage CT scanner specially designed for this purpose, conclusively demonstrate that supervoltage CT is feasible and completes the extension of CT to the highest possible X-ray energies. Furthermore, analysis of the supervoltage images provides convincing evidence that CT dynamic range, contrast sensitivity and defect detectability are not diminished, and may in some cases be enhanced, at supervoltage energies.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1991
- Accession Number
- ADA240625
Entities
People
- James H. Stanley
- Paul D. Tonner