Advancing NDE for Aerospace Structures

摘要

Performance requirements for advanced aircraft and missile systems seek higher capability such as speed, capacity and maneuverability but with an increasing emphasis on affordability. Higher performance and lower cost have traditionally been viewed as mutually exclusive goals. However opportunities exist in materials and processes selections that can provide low cost with high performance. In order to reap these benefits, nondestructive evaluation (NDE) and process control are being called into play with greater "up front" program emphasis than ever before. The development of increased measurement capability by NDE technologies; embedded sensor systems and process monitoring tools are key elements in the design and construction of modern high technology aerospace systems. A key approach to affordability in the manufacture of modern complex aerospace systems is the use of large unitized structures. Well-controlled processes, including joining/bonding techniques, will be required. Sophisticated nondestructive evaluation (NDE) at the process steps and final product will be required. The quality assessment of the product is moving from a uniform defect size specification to zoned criteria and fitness for service determination. Large unitized structures have a very high value. Nondestructive inspection of such a part that results in rejection by standard criteria will simply not be accepted without an engineering review. Wherever possible, the part will be saved because of the high investment. This trend toward larger structures of high value affects how NDE operations are performed and the data analyzed. The driving forces for the future and the impact on NDE are noted in Figure 1.