Abstract
We perform Operational Modal Analysis (OMA) through Frequency Domain Decomposition (FDD) on a test structure using a high speed camera. Using optical flow algorithms, brightness changes due to displacements of a test structure under load are translated into displacement data. By using a mirror, a split image is generated that enables a stereoscopic view of the structure and thus 3D information can be extracted from the high speed video footage.
This setup is used to determine the modal parameters of the structure, especially the mode shapes with high spatial resolution. The mirror that is used to gather a second point of view onto the image sensor enables a cost-efficient stereoscopic measurement compared to a two-camera setup. Moreover, it eliminates the need of synchronizing two separate signals. This is also why OMA is used instead of EMA: as no force signal needs to be recorded, we can perform a full-field modal analysis with inputs from only one single device.
The results are evaluated taking into account the accuracy as well as the complexity of the setup of the 3D measurements compared to a setup using triaxial accelerometers.
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Gille, M., Judd, M.R.W., Rixen, D.J. (2023). Stereoscopic High Speed Camera Based Operational Modal Analysis Using a One-Camera Setup. In: Di Maio, D., Baqersad, J. (eds) Rotating Machinery, Optical Methods & Scanning LDV Methods, Volume 6. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-031-04098-6_11
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DOI: https://doi.org/10.1007/978-3-031-04098-6_11
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