Method of Assessing Bond Integrity in Bonded Structures
First Claim
1. A method for assessing bond integrity at a region of a surface of a bonded material, the method comprising:
- a. producing transient heating in the region so that if the region overlies a disbond in the bonded material, membrane vibration having a vibration period is induced over the disbond; and
b. detecting any surface displacement at or adjacent the region with a large etendue interferometer having a response time sufficiently short to adapt to ambient vibrations and speckle changes, but substantially longer than the vibration period;
whereby the surface displacement can be used to determine whether a disbond is present.
1 Assignment
0 Petitions
Accused Products
Abstract
A technique for acoustic detection of a disbond within a bonded structure involves thermal excitation of the surface of the bonded structure to induce a lifting and membrane vibration and is applicable to laminates and coated structures, as well as foam core structures or a honeycomb structures. The technique does not require access to both sides of the bonded structure. A large etendue interferometer is used to provide surface displacement measurement. The surface displacement measurement can be analyzed both by frequency or amplitude to determine existence of a disbond by membrane vibration, and further a thickness of the disbond can be determined using traditional pulse-echo time analysis. The technique may allow detection of stick bonds.
20 Citations
35 Claims
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1. A method for assessing bond integrity at a region of a surface of a bonded material, the method comprising:
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a. producing transient heating in the region so that if the region overlies a disbond in the bonded material, membrane vibration having a vibration period is induced over the disbond; and b. detecting any surface displacement at or adjacent the region with a large etendue interferometer having a response time sufficiently short to adapt to ambient vibrations and speckle changes, but substantially longer than the vibration period; whereby the surface displacement can be used to determine whether a disbond is present. - View Dependent Claims (2, 3, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21)
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4. (canceled)
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5. (canceled)
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11. (canceled)
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12. (canceled)
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13. (canceled)
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22. An apparatus for assessing bond integrity at a region of a surface of a bonded material, the apparatus comprising:
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a. a generation laser beam for producing transient heating in the region so that if the region overlies a disbond in the bonded material, membrane vibration having a vibration period will be induced over the disbond; b. a large etendue interferometer for producing an interference in dependence on any surface displacement at the region, the large entendue interferometer having a response time sufficiently short to adapt to ambient vibrations and speckle changes, but substantially longer than the vibration period; and c. a detector for detecting the interference. - View Dependent Claims (23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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24. (canceled)
Specification