Experimental investigations on mechanical propertiesof 3D-printed tensegrity-inspired metamaterialsbased on 4-strut simplex module

The present study is focused on experimental investigations of mechanical properties of 3D-printed tensegrity-inspired metamaterials. Tensegrity systems have many advantageous features, such as: light weight, high stiffness-to-mass ratio, controllability, inherent attributes of smart structures, and unique mechanical behaviour. They may be applied not only in macro-scale, but they can also be used to create cellular mechanical metamaterials and lattices in various scales. Metamaterials are understood here as human-designed artificial materials, which do not exist in nature, and whose mechanical properties result from the morphology of the inner structure rather than from chemical or phase composition. Experimental studies on tensegrity metamaterials manufactured using 3D printing techniques are hardly present in the literature. This paper presents results of uniaxial compression tests carried out on a number of 3D-printed tensegrity-based modules corresponding to the metamaterial cells, differing in the manufacturing technology, parent material, and size. The following observations were made during the tests: one of the most important parameters that has a direct impact on the results is the elongation at break of the parent material; any inaccuracies at the production stage greatly affect the mechanical behaviour of the structure; it is crucial to ensure a free deformation consistent with the infinitesimal mechanism mode of tensegrity; a post-critical behaviour of the struts was clearly visible in the performed tests.