Energetic classifying of vibration modes in subspace stochastic modal analysis

As a consequence of progress in structure modal analysis, in-operation modal tests are more and more widely performed, thus providing a realistic characterisation of the system in its environment. In this framework, it is worthwhile considering the significance of identified modes. A solution could be to classify these modes according to their energy levels while the structure is operating; that would allow selecting the most powerful ones. The following paper investigates this possibility, taking into account the context of stochastic analysis, which means that the excitations are unknown.