Laser powder bed fusion of bio-inspired reticulated shell structure: Optimization mechanisms of structure, process, and compressive property

Abstract

Recent researchers show that the shell structure and truss structure are emerging categories of light weight structure with unique mechanical properties and high customization potential, but they are difficult to manufacture by traditional methods. Inspired by the diving bell of water spider, the reticulated shell structure designed in this work combines the characteristics of the truss structure and the shell structure, and is fabricated by laser powder bed fusion (LPBF). The effect mechanism of strut angle on the manufacturability, compressive behaviors, energy absorption property, stress distribution, and fracture morphology were studied by experiment and simulation methods. The results showed that the relative densities of reticulated shell structures increased with the increase of strut angle, which was due to the existence of a large proportion of overhang structures in the reticulated shell structures. The compressive load-displacement curves of all reticulated shell structures showed a similar trend, including three stages, which were elasticity, subsidence, and densification. The reticulated shell structure with the strut angle of 75° had the highest specific energy absorption and energy absorption capacity. Finite element simulation results revealed that, with the change of the strut angle, the stress concentration in the reticulated shell structure significantly changed and directly affected the compression behavior of structures. The structure with the strut angle of 75° exhibited the lowest stress concentration level at key locations, leading to the best compressive behavior among structures.