1. General principle

The aim of experimental modal analysis is to quantify the modal basis representative of the dynamic behavior of a structure in a given frequency band, this behavior being assumed to be linear. The focus here is on modal testing, in which point excitations are applied and measured.

We will therefore not be dealing with base excitations, rotating structures, structures exhibiting marked non-linear behavior, or operational modal analysis, which aims to identify the modal base without measuring the applied forces (which are generally the natural excitations experienced by the structure: aircraft in flight, road vehicles on the road, wind turbines in operation).

Consider a structure subjected to known dynamic forces $\left\{F\left(t\right)\right\}$...