Experimental-based modeling of a support structure as part of a full system model

Structural dynamic systems are often attached to a support structure to simulate proper boundary conditions during testing. In some cases the support structure is fairly simple and can be modeled by discrete springs and dampers. In other cases the desired test conditions necessitate the use of a support structural that introduces dynamics of its own. For such cases a more complex structural dynamic model is required to simulate the response of the full combined system. In this paper experimental frequency response functions, admittance function modeling concepts, and least squares reductions are used to develop a support structure model including both translational and rotational degrees of freedom at an attachment location. Subsequently, the modes of the support structure are estimated, and a NASTRAN model is created for attachment to the tested system.