In this study, an output-only crack localisation method based on the Hilbert–Huang transform is proposed for crack localisation in bridge-type structures subjected to a moving vehicle simulated by a moving oscillator. The proposed method can accurately identify the location of cracks without using the conventional computationally expensive model updating techniques. The new crack localisation method can be adopted using fixed sensor and moving sensor approaches. In the fixed sensor approach, an acceleration sensor is located on an arbitrary point of the bridge, whereas in the moving sensor approach, an acceleration sensor is attached to a moving vehicle. The efficiency of the fixed sensor and moving sensor approaches is assessed through several numerical examples. A comprehensive analytical study is also conducted to investigate the impacts of crack depth and moving vehicle characteristics (such as damping coefficient, natural frequency, and velocity) on the accuracy of the predictions. It is shown that the proposed crack localisation method using fixed sensor and moving sensor approaches could efficiently identify the location and localisation of the cracks in all cases. However, the results indicate that the accuracy of the fixed sensor approach is generally better than that of the moving sensor approach in the localisation of cracks with small depth.
Structural diagnosis of bridge using output-only vibration in moving vehicle laboratory experiment
