Damping behaviour analysis of 3d printed samples with pores

Abstract

3D printing offers the possibility of introducing pores into the material in a targeted manner. This results in a low-density material which can also act as a passive damping material with increased damping properties. Against the background of noise and vibration control, an adjustable damping behaviour is of technical interest. Strain- and frequency-dependent damping measurements were carried out at room temperature on rectangular samples made from polylactic acid which is a bioactive and biodegradable polyester. The samples were produced using a commercially available 3D printer. Different pore sizes and pore distances were realised. Afterwards, the impact on the damping behaviour was analysed. A monotonic increase in damping of both non-porous and porous specimens occured when the increase of material strain was noticed. The damping was dependent on the pore size but this became clear for larger pores. Pore spacing seemed to be less important. Frequency-dependent damping measurements of non-porous and porous samples showed a slight decrease in damping with the increasing frequency in the selected frequency range from 10 Hz to about 60 Hz. The results were significantly influenced by the pore size. A slight increase in material damping with the increasing pore spacing was observed. Further, “voids” (empty spaces) were found in the immediate vicinity around the pores which varied greatly in both length and width. Their individual influence on the overall damping must be taken into account. Only after a certain combination of pore size and porosity onwards, a dominant influence of these two parameters can be expected.