Discriminating physical poles from mathematical poles in high order systems: use and automation of the stabilization diagram

System identification from measured MIMO data plays a crucial role in structural dynamics and vibro-acoustic system optimization. The most popular modeling approach is based on the i modal analysis concept, leading to an interpretation in terms of visualized eigenmodes. Typically, the number of nodes is very high (often over 100), including modes with high damping and high modal overlap. The paper discusses a key problem of the system identification process: the selection of the correct model order and related to this, the selection of valid system poles. A multi-order approach, followed by a heuristic selection process is outlined. A visual representation of the pole behavior is presented and the possible routes to automation are discussed. The process is illustrated with typical complex datasets, including full-scale industrial tests.