Structural damage detection using constrained eigenstructure assignment

System health monitoring of aerospace vehicles is important not only for conducting safe operation but also for maintaining system performance. Structural health along with sensor and actuator malfunction must be monitored to perform the system health monitoring. As a step toward developing a system health monitoring scheme, this paper investigates structural damage detection using a constrained eigenstructure assignment. The eigenstructure assignment is selected for the investigation since it may be used not only to perform structural damage detection but also to monitor the sensor and actuator performance in a unified manner. To employ the eigenstructure assignment in the framework of structural modeling and modal testing, a concept of constrained eigenstructure assignment is developed. The constrained eigenstructure assignment makes it possible that the computed feedback gains correspond directly to the structural parameter changes. To demonstrate the capability of the approach, a 20-bay planar truss structure is employed. Modal tests are performed using 11 accelerometers for the undamaged structure and several missing member damage cases. Then the test modes are used to locate the missing member. Despite incomplete mode shapes and test inaccuracies, accurate damage detection is conducted. (Author)