Improving Mechanical Properties and Energy Absorption of Additive Manufacturing Lattice Structure by Struts' Node Strengthening

The lattice structure has unique performance and superior deformation behavior, which effectively stimulates the design and application of new lattice structures. The development of additive manufacturing technology makes it easy and efficient to manufacture complex lattice structures. However, it has been found that excessively high stress concentration exists at the struts' nodes during the compression of lattice structure. Therefore, three node strengthening strategies were proposed to reduce stress concentration, which were adding fillet at nodes, using circular arc transition and changing the angle of nodes. Firstly, lattice structures were manufactured by selective laser melting technique. The surface morphology of the lattice structures was observed by scanning electron microscopy. Then, the stress distribution and deformation mechanism of different lattice structures were investigated by quasi-static compression experiments and numerical simulation. Finally, the Gibson-Ashby model was adopted to predict lattice structures' modulus and strength. And the energy absorptions of different structures were compared. The results revealed that the deformation mode of the optimized structures changed from shear failure to layer-by-layer collapse. Compared with the hourglass lattice structure and gradient lattice structure, the mechanical properties of curve lattice structure were improved the most.

Automated summary

This research investigates three strategies to reduce stress concentration at the nodes of lattice structures and examines the mechanical properties and deformation mechanisms of different structures through experiments and numerical simulations. The results reveal that the curve lattice structure exhibits the best mechanical performance.