Structural health assessment under uncertainty

A generalized system identification procedure is presented to identify structural stiffness parameters at the element level using only limited noise-contaminated response information and completely ignoring the excitation information. The authors called it a GILS-EKF-UI method. The structures are represented by finite elements. The procedure detects defects by tracking the changes in the stiffness property of each element. The method can identify defect-free and defective structures even in the presence of relatively large amount of noise in the responses. Defects could be minor in nature. The method is very robust and can identify defects caused by different types of loadings including seismic loading. The research team at the University of Arizona is in the process of developing a nondestructive defect assessment procedure for existing structures and the GILS-EKF-UI procedure will be an essential component of that effort.