Nondestructive Evaluation of Structures

The process of implementing a damage identification strategy for aerospace systems is referred to as structural health monitoring (SHM). Here, damage is defined as changes to the material and/or geometric properties of these systems, including changes to the boundary conditions and system connectivity, which adversely affect the system's current or future performance. A wide variety of highly effective local non-destructive evaluation tools are available for such monitoring. However, the majority of SHM research conducted over the last 30 years has attempted to identify damage in structures on a more global basis and in a more autonomous manner. Recent research has begun to recognize that the SHM problem is fundamentally one of statistical pattern recognition, and a strategy to address this problem as it applies to aerospace structures is described herein. To conclude this discussion, technical challenges that must be addressed if SHM is to gain wider application in the aerospace industry are summarized. Keywords: damage detection; data normalization; feature extraction; health and usage monitoring; operational evaluation; pattern recognition; sensors; dtatistical classification; structural health monitoring; pattern recognition