Two-step structural damage detection method for shear frame structures using FRF and Neumann series expansion

Abstract

In this paper, a novel damage detection method for shear frame structures was presented. The proposed approach was derived from frequency response function (FRF) measurements before and after damage. Using a Neumann series technique, the damaged FRF data were expanded as functions of a truncated intact FRF matrix. The truncated approximate series equations with multiple frequency points were solved using the constrained optimization method. Nevertheless, a correlation of the damage detection solution vector was defined as the structural damage location index. Unlike existing methods, the effect of noise on damage detection was greatly suppressed by simultaneously increasing the number of equations and reducing the unknown coefficients. The proposed approach was validated numerically and experimentally with a 12-story shear frame structure model and a 7-story steel-frame structure, respectively. The results of different damage scenarios showed that the proposed method has good noise immunity and high accuracy.