Investigating Compressing Particle Damper Pockets in Beams Manufactured by Laser Powder Bed Fusion Additive Manufacturing

Components manufactured by laser powder bed fusion (LPBF) additive manufacturing can have particle dampers designed into the part by leaving unfused powder inside a defined pocket of the part during manufacturing. These pockets of unfused material have inherent damping capabilities that suppress the vibrations and potentially reduce component wear. Particle dampers have been shown to be a simple and effective way to increase the damping of a structural component manufactured by LPBF; however, the compressing effects of the particle damper pocket inside the beam have not been studied. The amount of unfused powder inside the pocket is difficult to control (or even measure) during manufacturing; therefore, this study reports preliminary investigations on the effects of energy absorption provided by changing the volume of the pocket. In this study, beams are printed with 316L stainless steel powder with single particle dampers. Thereafter, the cover of the pocket is deformed, decreasing the volume of the pocket. The energy absorption characteristics of the particle damper are quantified. The unfused powder pocket’s damping characteristics are assessed by observing the structure’s response to various excitation methods. An input-output relationship can be deduced using a reference accelerometer and an accelerometer mounted passed the damper pocket with respect to the fixity. With this relationship established, the magnitude of damping and the phase attributed to it is determined. Studying the damping characteristics of various compressed pocket sizes and powder quantities will provide helpful information to enhance particle dampers’ efficiency using LPBF techniques.