Comparing Frequency-Based and Modal-Based Substructuring on the Dynamic Substructuring Round Robin Benchmark

Dynamic substructuring enables to analyze the dynamics of complex systems on a substructure level. In experimental context, a successful substructuring prediction relies on reliable and accurate measurement acquisitions, as well as proper design of experiments and description of the interface dynamics. Depending on the quality and quantity of information stored, system dynamics, frequency range of interest, and interface connection, several strategies based on directly estimated transfer functions or identified modal properties may be adopted. In this chapter, a frequency-based substructuring and a modal-based substructuring approach are compared on a coupling prediction of a continuous/flexible-like connection on the SEM dynamic substructuring round robin testbed. The focus is on measurement setup (e.g., design of experiments, etc.), experimental modeling of the interface (e.g., discretization, reduction basis, additional fixtures, etc.), and data processing (e.g., filtering, selection, reconstruction…) to ensure a robust substructuring prediction given the assembly configuration and dynamics. Benefits and drawbacks of the applied strategies, as well as key assumptions and methodological differences, are highlighted. Both a numerical and an experimental application are presented.