Multiple damage location with flexibility curvature and relative frequency change for beam structures

The purpose of this paper is to seek efficient methods for multiple damage location in beam structures. Two methods are studied in terms of finite element model (FEM) simulations on beam structure. Firstly, a finite element model of reinforced concrete beam is established to compute changes in flexibility and flexibility curvature of the beam with various damage patterns, and sensitivities of flexibility and flexibility curvature for closely distributed damage patterns of various extents are also compared. Due to its high sensitivity to closely distributed damages, flexibility curvature is recommended for multiple damage location. Secondly, the full correlation between the relative frequency changes and the analytical frequency changes are confirmed with FEM analyses: therefore, the relative frequency changes, rather than the frequency changes themselves, are used in the multiple damage location assurance criterion (MDLAC) to increase the location efficiency. Numerous examples are presented to verify the two methods. (C) 2002 Elsevier Science Ltd. All rights reserved.