Rate- and temperature-dependent plasticity of additively manufactured stainless steel 316L: Characterization, modeling and application to crushing of shell-lattices

A combined numerical and experimental investigation is carried out on the quasi-static and high strain rate response of additively manufactured stainless steel 316L obtained through selective laser melting. The experimental program comprises experiments on uniaxial tension, shear, notched tension and mini-Nakazima specimens, covering a wide range of stress states and strain rates (from 10(-3) to 10(3)/s). An anisotropic quadratic plasticity model with Swift-Voce hardening and Johnson-Cook rateand temperature-dependence is identified to describe the behavior of the constituent base material under different stress-states and strain rates. Compression experiments at low and high loading speeds are conducted on elastically-isotropic shell-lattice structures to further validate the identified plasticity model in a structural application. It is found that the chosen plasticity model can describe the reaction force and deformation patterns of the smooth shell lattice loaded at different speeds and orientations with good accuracy. The experiments reveal that the additively-manufactured shell lattices are capable of sustaining macroscopic compressive strains of more than 60% without visible fracture of the cell walls regardless of the loading speed. The comparison with the results for plate-lattice structures of the same mass elucidate the great energy absorption potential of shell-lattices.