Strain estimation using modal expansion approach via virtual sensing for structural asset management

This study explores the concept of virtual sensing as a potential application for estimating dynamic strain in a virtual location. The study was carried out on a vertical cantilever beam which was used to represent a vertical structure. The acceleration responses were measured in four locations and, through Operational Modal Analysis (OMA) and Modal Decomposition and Expansion (MDE) techniques, was then estimated in a virtual location. The dynamic strain was then estimated in the same virtual location. First the measured acceleration responses were compared to predicted responses using OMA. This was done to update the finite element model and optimise the position of the sensors. From this point the dynamic strain could then be estimated in the virtual location using Modal Decomposition and Expansion. This methodology was then repeated for the same beam with additional mass attached to the top. The dynamic strains were then measured and compared to determine the effect of the additional mass on the structural response. The results from this study demonstrated the potential of this methodology to estimate and monitor real time dynamic strain in virtual locations