Damage detection in Armored Vehicle Launched Bridge (AVLB)
AVLB stands for Armored Vehicle Launched Bridge. A system was designed for performing damage detection and localization in AVLB using vibration data. Specifically, the damage detection method was based on a modified method of strain energy mode shapes.
Video on the bottom of this page shows the system in action.
The bridge was installed on airbags and excited by band-limited white noise. A scanning laser vibrometer was installed on a robotic gantry crane and could be positioned at any location above the bridge with accuracy of 5mm. A frequency response function (FRF) was computed between excitation measured by a force transducer and response of the bridge. A grid of points was scanned along each girder and displacement (bending) modeshapes were computed for the bridge. Then signal processing and a fuzzy expert system identified possible damage and its location.
Video of AVLB damage detection system