This Small Business Innovation Research Phase I project will develop a non-destructive inspection (NDI) method for remote diagnostics of critical structural components such as mechanical fasteners (bolts, welds, rivets, etc.) or advanced materials (composites). Utilizing an impedance based approach, damage in critical structural components or advanced materials can be detected by periodic remote inspection without removing the structural component or making costly visual inspection. By attaching small piezoceramic transducer materials (such as PZT wafers) to the components of interest, damage can be detected by changes in the structural impedance. Impedance monitoring is especially facilitated by the use of the PZT wafers which can simultaneously activate and sense structural response. PZT wafers respond mechanically to electric signals, producing a small deformation in themselves and the structure to which they are attached (host structure). The electrical impedance (voltage/current) of the PZT wafer therefore has a direct correlation to the mechanical impedance of the component. Should the components mechanical impedance change from damage or variations of the properties, the periodic remote inspection of the PZT electrical impedance will manifest the variation. The impedance method for remote NDI of critical structural components will have value as an inexpensive and labor-saving inspection method for critical bolts and other fasteners in aerospace and civil infrastructure applications. A family of fasteners for off-the-shelf application in such structures will also be developed with the NDI sensors in-place to provide a means for designers to include readily inspectable parts into structural designs.
