Vibration-Based Structural Damage Identification under Varying Temperature Effects

Abstract

Vibration-based methods are promising for damage identification; however, their capabilities for damage identification under temperature variations are usually limited. In the paper, a vibration-based nondestructive global damage identification method based on a genetic algorithm (GA) is proposed to identify structural damage location and severity under the influence of temperature variation and noise. The proposed method is verified by a number of damage scenarios of a three-span continuous beam and a two-span steel grid and shows good robustness under random noise levels. First, considering that the material properties of a structure and boundary conditions of a system are generally temperature-dependent, the relation between temperature and elastic and geometric stiffness matrices is introduced, and damage parameters along with temperature are defined as variables of the numeric model. Second, a GA is introduced where a new objective function with different weight coefficients, combined with frequencies and mode shape, is proposed and developed. Third, damage identification of a three-span continuous beam and a two-span steel grid under temperature variation is carried out numerically, considering changes of material properties and boundary conditions, and damage existence, location, and severity are accurately identified. Finally, it is shown that the proposed method is very robust even when the data are polluted with artificial noise.