Full-field force identification with high-speed digital holography

Abstract This paper proposes a full and large field, high spatial resolution, contact-less, and non-intrusive approach for force retrieval at different excitation regimes of mechanical structures. The inverse problem is based on the Force Analysis Technique where the measured displacement/velocity field is obtained from high-speed digital holographic vibrometry. With the full-field measurements, the analysis of harmonic and transient vibration sources is performed in both the spatial and temporal domains. The dense mesh of data points is advantageously used to solve the inverse problem of force identification (in terms of localization and quantification) which is regularized following a Bayesian approach. Experimental results for both stationary and transient regimes are provided. For the stationary regime, results are compared with those obtained from scanning vibrometer and exhibit quite good agreement, thus validating the proposed approach. For the transient regime the retrieved time dependence of the force is compared with the signal directly measured by a piezoelectric force sensor. Overall experimental results show very good agreement.