Structural intensity measurement for damage detection

Structural Health Monitoring (SHM) technologies are increasingly being identified as critical design elements for future aerospace systems and other high performance structures. SHM systems of the future will require advanced sensors and sensing techniques to reach their goals for structural damage detection on critical complex structures. Recently there has been interest in applying structural intensity for detecting damage in complex structures. Structural Intensity (SI) and power flow, which trace the vibration energy propagation through a structural system, have significant potential for use as a structural damage sensing metric. Structural intensity has been applied to vibration control and the study of energy flow in structures and machinery. Structural intensity is typically measured at several locations on a structure and health assessment is accomplished by detecting changes in intensity magnitude and direction within the structure. In this work, current methods for the measurement of structural intensity are reviewed, their potential applicability to structural damage detection discussed and measurement examples presented. The use, and insights gained, of applying computational techniques to explore damage development and optimize SI sensor placement are also presented.