In order to control vibrations of structures or to establish a fatigue life prognosis, knowing the natural frequency, vibration mode, and similar characteristics is a key requirement.
Mode analysis employs excitation of the target structure with a hammer or similar and measures vibration response using accelerometers or other suitable sensors. The acquired time data are then transformed into frequency data, i.e. transfer functions through FFT analysis. Inherent values (natural frequency, natural damping ratio, eigenvector) are determined with the curve fit method, and animation is used to visualize behavior at various frequencies.