Investigation On Mechanical Properties And Energy Absorption Of Superimposed Lattice Structure

The lattice structure is light in weight and has better resistance to buckling and impact.The structure maintains almost constant energy absorption efficiency during the compression process,which can be utilized as an energy-absorbing device.At present,the lattice structure has been applied in aerospace structures,transportation vehicles,and explosion and impact protection systems.In this thesis,a novel superimposed lattice structure has been designed.The mechanical properties and energy absorption have been investigated.It is expected that the lattice structure with high mechanical properties and high energy absorption can be achieved,which will have theoretical and practical significance.Three superimposed lattice structures(SR structure,BS structure,BR structure)are designed with 316 L stainless steel powder through the Selective Laser manufacture in this paper.The quasi-static compression and dynamic compression behaviors of the superimposed lattice structure samples were characterized.Furthermore,deformation mechanism and energy absorption of the superimposed lattice structure were analyzed by simulation.The experimental results show that the strength and stiffness of the superimposed lattice structure increase with the relative density.There are three obvious stages under both quasi-static and dynamic compression:the elastic stage with a small strain range,plasticity and densification period.The initial peak stress of the true stress-strain curve increases with the relative density.The quasistatic and dynamic compression behavior results of the numerical simulation superimposed lattice structure are basically consistent with the experimental results.Further studies have shown that the mode dominated by stretching and bending is the deformation feature of the superimposed lattice structure.The deformation mechanism is related to the position and proportion of the vertical rods in the superimposed lattice structure;the plastic platform of the BR structure dominated by inclined rods is far Lower than the BS and SR structures dominated by vertical rods;the superimposed lattice structure has obvious advantages in energy absorption,and its energy absorption is 14 times that of the traditional lattice structure with the same truss diameter;the energy absorption of the three superimposed lattice structures The best performance is the SR structure,whose energy absorption is more than 1.21 times that of other superimposed lattice structures,and its specific energy absorption is more than 1.47 times that of other superimposed lattice structures.