Fusion of NDT Data for Structural Integrity Assessment of Brazed Joints in a Cryogenic Engine Nozzle Exit Cone

Cryogenic engine nozzles are regeneratively cooled to obtain optimal combustion efficiency. To achieve this, axial channels are fabricated on the body of the nozzle and its divergent through vacuum brazing. During such a process, folds/bulges get developed at a few locations. The physical integrity must be examined at these flaw locations through suitable NDT techniques. Moreover, the remaining structural life must be assessed by assimilating quantitative stress, strain, and displacement data during the proof pressure tests (PPT). In addition to the above, presence of any active/growing defect should also be identified during the PPT. The abovementioned steps must go hand-in-hand to ensure the component’s structural integrity. This paper reports the fusion of data from three NDT techniques, such as infrared thermography (IRT), digital image correlation (DIC), and acoustic emission (AE), to accomplish the above-said procedure. The data accumulated from these techniques were correlated to evaluate the structural integrity of a nozzle divergent.