Structural damage localization from modal strain energy change

A method based on modal strain energy is presented for locating damage in a structure. This method makes use of the change of modal strain energy in each structural element before and after the occurrence of damage. Some properties of this Modal Strain Energy Change are given to illustrate its sensitivity in locating the structural damage. Information required in the identification are the measured mode shapes and elemental stiffness matrix only without knowledge of the complete stiffness and mass matrices of the structure. Several damage cases in a simulated structure are studied in which the effect of random error in terms of measurement noise in the mode shapes and systematic error in terms of errors from incomplete measurements are considered. This method is then applied to detect damage in a single-bay two-storey portal steel frame structure. Results illustrate that the MSEC is sensitive to damage, and the proposed method is simple and robust in locating single or multiple damages in a structure. (C) 1998 Academic Press.