Hybrid Eulerian–Lagrangian framework for structural full-field vibration quantification and modal shape visualization

Abstract

Vibration measurement and modal analysis under a high spatial and temporal resolution have high significance for revealing inner structural characteristics. This work develops a hybrid Eulerian–Lagrangian framework for structural full-field dynamic vibration quantification and modal shape visualization and validates its performance through vision-based vibration experiments. By assuming a linear vibration system, modal responses that are estimated from the vibration signals on a structural surface provide a reliable basis for manipulating temporal and spatial vibrations in Eulerian motion processing. Then, dynamic spatial motion can be quantified by using the improved non-rigid image registration algorithm. Meanwhile, from the Lagrangian perspective, high-quality visualization of modal shapes is implemented by compensating spatial motion according to magnified dense displacement fields. The experiment results showed that the proposed hybrid framework has superiority in controlled modal tests and has potential for more practical applications.