Design And Mechanical Behavior Of Multilayer Gradient Lattice Structure

Using the grasshopper plug-in of rhino,the mathematical and parametric modeling of the topology optimized cell structure is carried out,and the uniform and density gradient lattice of two kinds of cells are established.The quasi-static compression analysis of two kinds of uniform and gradient cell density composite structure is carried out,and the experimental results are verified.The internal stress distribution,deformation mode,bearing capacity and energy absorption characteristics are analyzed.Based on ABAQUS / explicit,the finite element models of two kinds of cell lattice structure with uniform and gradient element density are established,and then the dynamic mechanical response is simulated.In the quasi-static mode,the lattice structure of ff-bcc has stronger strength and energy absorption characteristics,the uniform lattice structure has stronger bearing capacity than the gradient lattice structure,but the energy absorption characteristics are weaker than the gradient combination lattice structure.At the same time,the lattice structure shows obvious strain rate sensitivity.In transition mode and shock wave mode,the density strain,yield stress,platform stress and specific energy absorption of lattice structure with different cells increase with the increase of loading rate.At the same loading rate,the positive element density gradient combination shows the best load-carrying capacity and the best energy absorption efficiency.The lattice structure of different cells shows obvious strain rate sensitivity,and the lattice structure of F-Octa element with positive gradient is the most sensitive.The results show that the negative gradient composite lattice structure has the lowest yield stress at the support end in the impact velocity range studied,which has the best effect for the protection of personnel safety.At the same time,the negative gradient structure has lower stress at the impact end,which can be used to protect the impact object.The three-dimensional lattice structure has the characteristics of impact resistance,energy absorption,light weight and so on.The gradient composite lattice structure can be considered as a protective structure in aerospace,engineering and other fields in the future.Therefore,it is of great theoretical value and engineering significance to study the static and dynamic physical properties of new lattice structure materials.