A Comparison of Modal and Wave-Based Damage Detection Approaches for One-Dimensional Structures

摘要

Over the past two decades there has been an extensive amount of research in the area of structural health monitoring and the development of modal-based damage detection algorithms for complex structural systems. Most of these damage detection methods have been developed using modal frequencies and mode shapes as indicators to identify the presence, location and amount of damage. However, modal frequencies and mode shapes represent global dynamics of a structure and are not sensitive to a structure's local damage. On the other hand, the vibratory response of a structure can be represented by the superposition of traveling waves propagating along a complex structural network. Thus, implementing "virtual controllers" and eliminating geometric boundary conditions, a dereverberated transfer function can be obtained. Since the dereverberated transfer function represents the direct path of energy transmission across a structure, it can be used to infer damage in a structure by tracking how variations in local element properties affect the propagation of incident energy through the structure. In this paper, a comparison study has been carried out in order to determine the advantages and disadvantages of a damage detection approach based on the dereverbrated transfer function (DTF) response when compared to three modal-based approaches, including optimal matrix updating, sensitivity-based and eigenstructure assignment damage location methods.