On the role of spatial resolution in advanced vibration measurements for operational modal analysis and model updating

With the evolution of the electronics in hi-speed cameras for digital image correlation, another full field approach is emerging in the vibration engineering community. As for other full field measurement technolo- gies (like SLDV or dynamic ESPI), the displacement patterns that can be extracted have much higher spatial resolution than ordinary measurements, but with the great potential of sufficiently easy in-situ acquisitions for operational modal analysis. This work addresses the question whether OMA and Model Updating can usefully exploit the spatial data redundancy available in Hi-Speed Digital Image Correlation time histories for low cost image based & output-only tests. The impact of the extended channel set is shown on the ex- perimental identification of a lightweight structure like a thin vibrating plate and on its numerical model refinement. The estimated and calculated shapes are compared as function of the spatial refinement. Details on tests and identification procedure complete the discussion.