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Microwave Photoelasticity: A Resonant Wavelength Approach Applied to PEEK PolymerEvery nondestructive testing (NDT) technique has its unique set of advantages and limitations. Currently, the only existing noncontact NDT method capable of measuring sub-surface stresses, in optically opaque materials, at near-real-time speeds and over large areas is Microwave Photoelasticity (MP). This paper presents a new MP approach, which correlates changes in resonant wavelengths to changes in stress. In addition to a theoretical outline of the approach, the design and operation of an instrument capable of conducting these measurements is described. Finally, the technique is demonstrated by conducting measurements on polyetheretherketone, commonly known as PEEK, polymer. Between the W-Band frequencies of 105 to 115 GHz, PEEK’s stress-optic-coefficient was determined to be of 𝐶𝐶 = −0.20 ± 0.02 1/GPa.
Document ID
Document Type
Technical Memorandum (TM)
Schemmel, Peter J.
(NASA Glenn Research Center Cleveland, OH, United States)
Waldstein, Seth W.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
March 30, 2020
Publication Date
March 1, 2020
Subject Category
Nonmetallic Materials
Report/Patent Number
Funding Number(s)
WBS: 109492.
Distribution Limits
Work of the US Gov. Public Use Permitted.
Technical Review
Single Expert
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