During the recent pressure system recertification effort at the von Kármán Gas Dynamics Facility at Arnold Air Force Base, the Arnold Engineering Development Complex (AEDC) Nondestructive Testing and X-ray Lab team members identified a crack-like flaw in a high-pressure vessel but were able to implement a technique that allowed the vessel to remain in service.
According to Ken Delaney, Fitness for Service (FSS) analysis was used to determine if the vessel could remain in use, and if so, its remaining life and the frequency it would need to be inspected. “Depth of the flaw is a critical factor in the FFS analysis,” Delaney said.
Delaney, along with help from his colleagues Bart England, James Lucas and Ricky Dycus, developed a radiographic technique to determine the flaw’s depth.
“To validate the technique, a mock-up was fabricated including simulated flaws,” he said. “This technique provided confidence in the flaw depth measurement and supported the FFS process, which in this case allowed the vessel to remain in service with an inspection interval of two years.”
This technique is now being used on flaws in several other vessels undergoing the recertification process.
September 27, 2017