Experimentalmodal analysis (EMA) has a wide range of applications. It allows to identify the dynamic characteristics of a system for design, dimensioning, monitoring, etc.
To apply the techniques of experimental modal analysis (EMA), the source of the excitation must be known. In addition, the excitation and response of the system must be measurable. In the field of Structural Health Monitoring (SHM), and in particular in the context of continuous vibration monitoring, it is important to identify the modal parameters on a continuous basis to ensure that the system is functioning properly.
In this context, and specifically in the field of civil engineering, MEA techniques are no longer feasible because the excitation is generally unmeasured. Indeed, it is necessary to identify these parameters from the response of the structure alone, in operation, to an ambient excitation.
Operational Modal Analysis (OMA)
Operational Modal Analysis (OMA) is not constrained by these requirements and is clearly the perfect candidate for the job. Indeed, it considers a perfectly random excitation and estimates the modal parameters from this assumption.
Methods?
Finally, several methods exist in the literature, which can be classified according to the application domain: frequency domain, time domain or time-frequency domain. The difference between these techniques lies in the speed of the algorithms and the robustness to noisy data. For a more general and detailed presentation of these techniques, the reader can
consult THE REFERENCE in this field: Rytter, A. (1993). Vibrational based inspection of civil engineering structures.
