Parameter effecting the experimental determination of modal properties

The investigation of structure dynamic behavior can be done by finding modal properties, which are based on the relation of force and vibration response. The information about exact force value is in most application unknown, but the investigation can be done for unit magnitude of force. In case of using modal exciter, the force applied to structure is transferred by connection between modal exciter and structure. The stiffness of connection part can affect the dynamic behavior and change the modal properties, or response of investigated part, because of additional modal properties of connection part. This article is focused on the influence of two different rod stiffness during modal properties identification. The modal exciter is used to find potential critical frequency during decreasing frequency. The affect is evaluated on the surface normal velocity as well as acoustic pressure. The stiffness of rod significantly affects the dynamic response of structure and based on that can add frequency, when the emitted noise is high