Modal Strain Energy-Based Model Updating Method for Damage Identification on Beam-Like Structures

Abstract

Modal strain energy is a sensitive dynamic characteristic for nondestructive damage identification. In previous decades, it was widely used in damage index methods for localization of damage. However, these kind of methods often make misjudgments, especially for beam- and plate-like structures, because their angular displacements cannot usually be directly measured, which plays an important role in calculating element modal strain energy. In this paper, using the Gaussian smoothing technique and a laser scanning vibrometer, a new modal strain energy-based model updating method is proposed for damage assessment of beam-like structures. This method can determine the location and severity of damage at the same time. It calculates the experimental modal strain energy independently from the element stiffness matrix to reduce measurement noise and is baseline free because the mass matrix used for normalization is considered unchanged. A simulated one-crack simply supported beam, a simulate Π–shape framework, and an experimental two-crack cantilever beam are used to demonstrate the effectiveness and robustness of the proposed method. The results show that this method can accurately locate the damaged elements and enable an acceptable assessment of the severity of damage.