Compression behavior of 316L diamond lattice structures fabricated via additive manufacturing with variable cell sizes

The unit size effect of 316L diamond lattice structures was systematically investigated through experiments, theory, and simulations. Experimental tests demonstrated that reducing the cell size to 5 mm and 2.5 mm enhances the load carrying capacity and energy absorption of the structures. Additionally, analytical solutions were developed to acceptably estimate the elastic modulus and yield strength of diamond lattice structures. Finite element simulations, incorporating elastic, plastic, and ductile damage models, were utilized to depict the entire deformation evolution at different strain levels. These simulations were found to be precisely consistent with experimental observations. The results confirmed a transition from non-uniform deformation to uniform large-scale plastic deformation. This transition is attributed to either locally fractured struts caused by longer struts in structures with large cell sizes or largely deformed, non-ruptured short beams in structures with smaller cell sizes. Comparisons with previous reports indicated that the current structures with a cell size of 2.5 mm exhibit outstanding mechanical performance, making them desirable candidates for engineering applications.