Model reduction and energy analysis as a tool to detect spurious modes

Linear system identification is an important and useful approach in experimental modal analysis. It allows for the extraction of resonance frequencies, damping ratios and mode shapes of a vibrating structure. In order to reduce the bias on the estimates, the model order is usually chosen quite high. This often results in the appearance of non-physical, or so-called spurious modes. In this paper we will show that many spurious modes can be removed from the obtained model using ideas from model reduction and looking at the energy contained in these modes.