Forced-response characterization of PBF-LB/AlSi10Mg particle dampers with thin and flat cavities

Abstract

Powder Bed Fusion (PBF) enables the production of complex geometries which offer the opportunity to manufacture lightweight, stiffness-optimised or integrally designed components. Although these properties are usually advantageous for the performance in many applications, they pose disadvantages under vibration as they lead to low damped components. These are prone to high vibration amplitudes which result in higher sound radiation and a reduced lifetime. Particle damping can counteract these disadvantages. By including cavities during the design process, unmelted powder remains inside the component after its production. This powder dissipates energy under vibration by inelastic impacts and friction in particle-particle or particle-wall-interactions, increasing the damping characteristics of the component. In this work, additively manufactured AlSi10Mg specimens with cavities are investigated with respect to their damping characteristics by experimental modal analysis. The focus of the investigation is on thin and flat cavities that can be easily integrated into components without adapting the external geometry. The damping characteristics in dependence on excitation amplitude and mode are quantified. The extent to which settling effects of the powder during shaking influence the damping is analysed. The vibration of the specimens is forced by an electrodynamic shaker and their response is measured contactlessly via Scanning Laser Doppler Vibrometry (SLDV). A damping effect of up to 564% depending on the mode, excitation amplitude and specimen can be achieved. In addition, a significant settling effect of the powder which hampers the damping effect is identified by CT scans and modal analysis.