Damage Assessment in Beams using Vibration Characteristics

Abstract

Vibration-based damage detection methods use measured changes in vibration characteristics to evaluate changes in physical properties that may indicate structural damage or degradation. The basic idea is that modal parameters (notably frequencies, mode shapes, and modal damping) are functions of the physical properties of the structure (mass, damping, and stiffness). Changes in the physical properties will therefore cause changes in the modal properties. Any reduction in structural stiffness and increase in damping in the structure may indicate structural damage or degradation. This paper develops a comprehensive procedure based on these principles, to non-destructively assess damage in beam type of bridges, using finite element techniques supported by experiments. Using the results from modal analysis of calibrated finite element models, algorithms based on flexibility and strain energy changes before and after damage are obtained and used as the indices for the assessment of the structural status. The effectiveness of the proposed procedure is demonstrated via numerical examples.