Modal Moment Index For Damage Detection In Beam Structures Using Experimental Modal Analysis

摘要

Health monitoring and damage detection in structures such as airframes is crucial to their safety and performance. Damage-induced changes in natural frequencies, damping ratios and mode shapes can be detected using experimental modal analysis (EMA), which has recently enjoyed intense research for application in structural health monitoring. A main theme of existing research has been to formulate a parameter, calculated using the measured changes in eigenparameters, which exhibits a significant "jump" at the damage location. Therefore, a damage-sensitive parameter can be used to localize the damage. It should likewise minimize the likelihood of false indications or of missing damage. In this paper, experimental modal analysis of undamaged and damaged cantilevered beams is performed to obtain the MMI Modal Moment Index for damage detection and to validate the results of the MMI using the Finite Element Method that was presented in previous papers. While localizing the damage, the experimental Modal Moment Index (MMI) for damage detection in beams is proved to be closely related to the numerical Modal Moment Index (MMI). Experimental MMI shows significant jump at the damage site and its value very close to the true damage. Eventually, MMI is shown to locate and quantify the severity of damage in beam structure. Consequently, MMI is judged to be an attractive damage parameter.