Structural repair having optical witness and method of monitoring repair performance

摘要

A structural repair includes a tell-tale optical witness that allows the health of the repair to be visually monitored. The optical witness includes a stress sensitive fluorescent dye that shows changes in local strain/stress patterns when the repair is subjected to electromagnetic energy of a particular wavelength. The dyes fluoresce more or less strongly as a function of the local stress/strain.

主权项

1. A method of monitoring changes in a patch bonded to a structure, comprising:
scarfing the patch into the structure, the patch comprising a number of fiber reinforced resin plies scarfed into the structure; placing a composite ply over the patch and over a portion of skin of the structure adjacent to the patch, the composite ply comprising a mechanochromatic dye having an optical behavior that varies in response to changes in stress indicated in the composite ply; cocuring the composite ply and the patch; recording a baseline image representing the optical behavior of the composite ply at a time that the composite ply and the patch are cocured, the baseline image including a first stress profile for the patch as indicated by the composite ply; periodically checking the composite ply for changes in the optical behavior of the composite ply including obtaining a new image of the composite ply, the new image representing the optical behavior of the composite ply and including a new stress profile for the patch as indicated by the composite ply, the periodic checking including subjecting the composite ply to electromagnetic energy of a preselected wavelength, and recording the optical behavior of the composite ply, wherein recording the optical behavior of the composite ply includes collecting photoluminescent quantum yield and fluorescence emission spectra from the composite ply; and comparing the first stress profile and the new stress profile.