Carbon-carbon and filament wound composties not only offer unique mechanical properties and capabilities, but are difficult to inspect and determine manufacturing integrity. Defects of interest are variations in density and chemical species, voids, and cracks. A new imaging technology, zt, has been developed which is intrinsically tomographic, images in planes parallel to the object surface, and is sensitive to chemical species and density. It is the optimal imaging technique for the defects and materials of interest here. Phase I will consist of utilizing existing equipment to scan parts supplied by the air force rocket propulsion laboratory (afrpl) in order to demonstrate the feasibility and sensitivity. It is expected that the parts supplied will have the following defects at a minimum: delaminations (lcm x lcm frontal areas, 1000, 500, 250, and 125 microns thick), density variations (lcm x lcm frontal area, 10, 5, 2, 1, and 0.5%), and porosities (hole sizes to vary and their density to vary to cause similar overall density variations as indicated for the density variation samples). In addition phase I will include an engineering study that will identify modifications to our standard systems that are required to optimize the zt technique for the problem of interest. Phase II will produce a prototype system that could be used in a laboratory setting.
