Investigation on the Acoustical Transmission Path of Additively Printed Metals

When additive manufacturing is used, the freedom of design plays a decisive role. It allows designers of mechanically stressed parts to generate special functional surfaces, integrate very efficient conformal cooling channels, or adapt the parts to the specific load in order to increase the stress ratio. In combination with the functional principle of particle dampers, the usage of metal additive manufacturing could be useful to implement damping directly in the transmission path of machine parts and elements. To achieve this goal, it is necessary to qualify the influence on the damping capability of the particles, outer geometry, frequency behaviour and the shape of the inner geometry. In this approach, different inner geometries are used to analyse the distinctions of damping behaviour caused by unmelted metal powder. The focus lies on the geometrical shape of the inner geometry. It is recognisable that the shape has a non-negligible impact on the dynamic behaviour of the structure. The results show that structures with a high number of sharp edges in the inner shape oriented orthogonally to the excitation or under a certain angle provide a better energy decay than structures without an inner shape or a force-parallel oriented shape.