Mechanical characterisation of additively manufactured PA12 lattice structures under quasi-static compression

Abstract

The primary advantage of lattice structures over other cellular structures is the possibility of obtaining higher mechanical properties combined with lower weight. This paper describes the quasi-static mechanical behaviour of eight lightweight lattice structures of various tessellated unit cell topologies using finite element (FE) analysis. Three types of structures were additively manufactured with polyamide (PA12) material using the advanced Multi Jet Fusion technology and were tested under quasi-static compressive loading. The experimental results were used to validate the FE models of the lattices. We compared specific mechanical properties of all eight structures designed with an identical strut diameter of 1 mm or an identical relative density of 0.095. Such comparisons provide a different order of preference for the lattice structures. Based on Maxwell’s stability criterion, the current eight structures are of bending-dominated nature; however, these structures may exhibit stretch-dominated behaviour due to a reasonable amount of struts aligned in the direction of the external load. An excellent combination of stiffness, strength, and energy absorption can be obtained by the structures, when the load is applied in a specific direction with respect to the strut elements.