An Experimental Study of the Pseudo-local Flexibility Method for Damage Detection of Hyper-static Beams

An Experimental Study of the Pseudo-local Flexibility Method for Damage Detection of Hyper-static Beams

Many vibration-based structural damage detection techniques that diagnose the damage imposed on a structure based on structural dynamic characteristic parameters have been proposed in the last two decades. One promising approach which has been proposed recently is the local flexibility method. The local flexibility method, which is based on virtual forces that cause nonzero stresses in a local part of the structure, can estimate the damage locations and local stiffness variations of beam structures. The structural modal parameters identified from the ambient vibration signals both before and after damage is the key information for the local flexibility method. In this study, non-local virtual forces which cause concentrated stresses in a local part and nonzero stresses in the other parts of a structure are utilized. The theoretical basis of the proposed method is derived, followed by validation of the method with a continuous steel beam experiment. The results illustrate that the non-local virtual forces can determine the local variations of stiffness for a beam more accurately with less identified modes. Therefore, the feasibility of the proposed method is higher because a limited number of high quality modes can be identified in real world applications.