Fault detection filter applied to structural health monitoring: experimental results

A model based fault detection filter is developed for structuralhealth monitoring of a simply supported beam. The structural damagerepresented in the plant model is decomposed and is shown to reduceto a fault direction vector maintaining a fixed direction. Accordingto detection filter theory, this fault detection vector undercertain circumstances can be uniquely detected and identifiedthrough an invariance in the direction imposed on the faultdetection filter residuals. The design algorithm uses a lefteigenstructure assignment approach. The filter is applied to datafrom an aluminum simply supported beam with 4 piezoelectric sensorsand 1 piezoelectric actuator. By exciting the structure at the firstnatural frequency, a 5 mm saw cut made to one side of the beam,is detected and localized. Copyright 2005 IFAC.