Metamaterials with auxetic behaviour have a great potential for a new generation of load-bearing lightweight sandwich structures due to their outstanding energy absorption behaviour. As a result of their negative Poisson's ratio, component cross-sections increase under tensile loading transverse to the loading direction and decrease conversely under compressive loading. This contribution describes experimental and numerical investigations with the finite element method on the load-deformation behaviour of sandwich structures under bending operations with differently oriented auxetic cores and honeycomb cores made of PLA-based polymers with different specifications and degrees of crystallisation. A star-shaped auxetic structure was chosen and compared with hexagonal honeycomb cores of similar thickness of the structural elements. The fabrication of the specimens was carried out by fused layer modelling and the materials were characterised microscopically as well as by indentation and thermal analysis methods. The results showed that the advantages of the auxetic structures in energy absorption were clearly evident for certain orientations to the loading direction and that the viscoelastic material properties influenced decisively the structural deformation behaviour.