Investigation On Selective Laser Melting Additive Manufacturing And Mechanical Properties Of Bio-inspired Diving Bell Structure

The diving bell,the residence built by water spiders,could withstand the impact load of water flows with different flow velocity from various directions.Therefore,it exhibits excellent shock absorption and impact resistance.In this paper,inspired by diving bells,the shock-absorbing and compression-resistant bio-inspired structures with different levels were designed,and Al Si10 Mg bionic components were manufactured by selective laser melting technology.The effects of laser process parameters and structural parameters on the mechanical properties of bionic structures were systematically studied by combining experimental testing with finite element simulation.The results showed that due to the existence of a large proportion of overhang structures in the bionic diving bell structure,during the laser processing,the cooling rate and temperature gradient in different regions resulted in differences in pore distribution and microstructures,which affected the mechanical properties of the structure.The components,fabricated under 400 W laser power and 2200mm/s scanning speed,exhibited the best mechanical properties.Using the optimized laser process parameters,the primary-level bio-inspired diving bell components with different structural parameters was formed,and the structural deformation process,fracture morphology,stress distribution and fracture mechanism were systematically studied.The study found that the primary level structures with different structural parameters exhibited similar deformation trends during compression.The compressive strength of components increased with the increase of strut angle and strut diameter;the ductility of components decreased with the increase of strut diameter,and increased first and then decreased with the increase of strut angle.When the strut angle was 75° and the diameter of the strut was 1.25 mm,the primary-level bio-inspired diving bell components showed the best compression performance,and the specific energy absorption values were(1.45 J/g)and(1.77 J/g),respectively.Based on this optimized primary-level structure,cross-linked structures and multi-level structures of the bio-inspired diving bell were designed and fabricated.Finite element simulation results and experimental test data revealed that the addition of multi-level structures could effectively improve the ductility,compressive strength and compressive properties of the bio-inspired diving bell structure.Heat treatment was also conducted on the SLMed bio-inspired diving bell components to further improve the compression performance of bio-inspired diving bell components.It can be found that after heat treatment,the energy absorption and specific energy absorption was increased by 229.3% and92.3%,respectively.