Influence of the vibrating source behavior and source side excitations on the Interface Completeness Criterion

In the framework of component-based transfer path analysis (CB-TPA), the Interface Completeness Criterion (ICC) is used to select the mobility completeness, i.e., the number of degrees of freedom (DoFs) at the interface between a vibrating source and a receiving structure. The calculation of the ICC is similar to a coherence function with values between 0 and 1. The higher the ICC, the better the completeness of the mobility. Although ICC has shown promising results, its application remains ambiguous. The influence of source side excitations and the behavior of the vibrating source have not been investigated. In this study, ICC is computed numerically in the case of a rigid vibrating source connected to a plate. Full completeness provides high ICC values, while completeness along a single DoF, normal to the structure, provides low ICC values, which may suggest a poor assessment of the on-board velocity. However, it is shown that the on-board velocity is perfectly estimated with the CB-TPA when the source behavior is simple. Discrepancies appear when the source behavior becomes more complex, but the link between these discrepancies and ICC is not obvious. The influence of source side excitations during ICC calculation is also investigated in the case of the Z completeness. It is shown that the number and orientation of the source side excitations govern ICC values and therefore should follow the source behavior, which is normally unknown. The numerical results are confirmed by the experimental study where similar results are obtained.