Damage location vector: A non-destructive structural damage detection technique

This paper presents a method for structural damage detection using frequency response functions (FRF) obtained from non-destructive vibration tests. It investigates the case of early structural damage in which there is no appreciable change in mass and damping. The resulting change in structural stiffness matrix is reflected in changes of FRF data which can be exemplified by the evaluation of damage location vector (DLV). This evaluation requires the dynamic stiffness matrix of the undamaged (virgin) structure and the change in frequency response functions of the currently damaged structure. In this paper the former is obtained from a finite element model of the virgin structure and the latter are obtained from the finite element modelling (FEM) and from impact hammer test. The method is applied to a space truss structure and a plate structure. Effects of noise, both numerically simulated and measured are also investigated. Preliminary results show that this method of Damage Location Vector can overcome the problems of coordinate incompatibility and noise and deliver encouraging results on damage detection.