4. Application in Modal Analysis, Model Updating, and Damage Detection

Experimental modal analysis has developed into a major technology for the study of structural dynamics. Complex structural dynamic responses can be represented using decoupled vibration modes, each of which is a single-degree-of-freedom (DOF) system governed by its natural frequency and mode shape. The study of the dynamic characteristics represented by modal properties, including the natural frequency and mode shape, is referred to as modal analysis. Theoretical modal analysis solves the differential equations of the motion (i.e. the analytical model) of a structure to compute the structure’s modal properties. Experimental modal analysis, on the other hand, primarily concerns the determination of the modal properties by conducting vibration tests on the structure and analyzing the acquired input and output measurement data. Whether the object is a turbine blade rotating at high speed or a bridge sustaining traffic and strong wind loads, experimental modal analysis has been widely applied to a variety of mechanical, aerospace, and power-generation structures, primarily to validate and improve their structural designs.