The model-based identification of frequency response func tions is of central importance in the context of the analysis and evaluation of dynamic deformation behavior and process stability of machine tools. The significance of this frequency response is determined essentially by the accurate consideration of damping. Local damping in pre-stressed gaps makes it a significant portion of the system damping, in which the effect depends on the preload and the stress in the various vibration forms. This article presents recent results regarding the experimental determination of the attenuation and the derivation of appropriate model parameters.