Weight reduction in dynamically loaded systems through the effect of damping in bolted joints

Abstract

In order to reduce vibration amplitudes, the MFPA Weimar is investigating joint damping. The effect is based on the relative displacement between two components between which a surface pressure acts. In this case, the surface pressure is applied by a bolted connection. The damping behavior is dependent on normal force and amplitude. Decay tests clearly show that it is not possible to approximate the curves due to the viscous behavior (exponential decay function). The superposition with Coloumb's friction leads to a new damping model, especially in the initial range. The aim is to set up a numerical model in order to be able to take the local damping effects into account in the development of components. For this purpose, zero thickness elements (ZTE) are introduced into the joint in the FE simulation and provided with a constitutive model that can represent the energy dissipation. The ZTEs are parameterized as a function of material, surface pressure and surface roughness. The amplitude reduction, which is often achieved by a frequency shift of the natural frequencies via tuned mass dampers, is replaced and thus contributes to lightweight construction.

Full Paper