Detection of Stiffness and Mass Changes Separately Using Time Series Analysis with Output-only Vibration Data

摘要

Operational effects on the structures (such as mass changes due to traffic crossing a bridge) introduce uncertainties in the damage detection process. When such changes and structural deteriorations happen simultaneously, damage detection becomes more complicated in defining how changes in mass and stiffness affect the changes in the structural properties and eventually the collected data. Thus, this paper focuses on developing a new methodology to detect changes in stiffness and eliminate operational effects e.g. mass separately based on a novel time series approach using output only vibration data. In this methodology, the difference Autoregressive moving average models with exogenous inputs (ARMAX) coefficients are utilized as Stiffness Damage Features (SDFs) and Mass Damage Features (MDFs) to determine the existence, location and severity of the damage or mass change. The shear type IASC-ASCE benchmark problem was utilized to verify the approach. The results show that changes in mass and stiffness can be clearly detected and damage's severity, location are also revealed successfully. Current limitations and plans are also discussed.