Mechanical characterisation of auxetic cellular structures built from inverted tetrapods

The paper is concerned with mechanical behaviour characterisation of auxetic cellular structures built from inverted tetrapods. The auxetic cellular structures were fabricated from the Ti-6Al-4 V alloy powder using the selective electron-beam melting method (SEBM). The fabricated specimens were experimentally subjected to different loading conditions by varying the loading direction and velocity (strain rate). In addition, the influence of the porosity on the mechanical response and deformation behaviour was analysed based on experimental compression tests supported by infrared thermography. The experimental results show that the porosity and loading direction have a major influence on the mechanical response, while the strain rate influence is negligible at analysed strain rates. The experimental results were also used to validate the computational lattice model of analysed structures computed by the LS-DYNA finite element code. The experimental and computational results were in good agreement for most of analysed geometries and loading cases.