Application of variational mode decomposition in vibration-based bridge damage detection

Bridges are critical infrastructure that require continuous structural health monitoring to ensure safety. Vibration-based methods utilize changes in dynamic response for damage detection. This study applies variational mode decomposition (VMD), a signal analysis technique, to detect damage in a three-span beam bridge model subjected to moving loads. A finite element model is developed to represent the bridge-vehicle interaction, and damage is simulated by reducing flexural stiffness. Sensors placed on each span record vibrations during vehicle passage. VMD decomposes the signals to analyze for damage indications. Different damage levels (30-50% stiffness reduction) and locations (each span) are evaluated. Vehicle speed is also varied to assess its effect. Damage is identified as peaks in the instantaneous energy diagrams of decomposed signals, correctly indicating the axle locations. Detection improves with sensors nearer the damage and lower speed. The results demonstrate VMD's ability to detect and locate damage without a baseline, indicating its potential as a non-baseline vibration-based damage detection method for bridges.