Research On Compression And Energy Absorption Characteristics Of Lattice Structures Based On Cell Parameters

Lattice structure is a support structure with good mechanical properties and structural integrity,with lightweight and energy-absorbing application properties and a large internal space that allows the structure to be designed with higher stiffness and load-bearing capacity without destroying the original material properties.Lattice structures are usually composed of multiple cells,and better mechanical properties are obtained by connecting the local structures inside each cell into a whole.Therefore,this thesis focuses on the effective compressive mechanical behavior of the cells,establishes a finite element model capable of evaluating their performance,and investigates the deformation failure mechanism,compression and energy absorption characteristics of multilayered dot matrix structures under compressive loading.In this thesis,the compressive and energy-absorbing properties of two multi-rod configuration lattice structure(Kagome structure and Bcc structure)are investigated.By changing the structural parameters of the kagome and adding 2 mm reinforcement plates between each layer of kagome,a total of 24 kagome structures were modeled,and their design-related parameters,such as support rod inclination and support rod diameter,were related to the relative density of kagome elements of each kagome structure.The above models were simulated by quasi-static compression finite element simulation,and some models were fabricated and tested by 3D printing using polyamide 12 as the structural material to verify the accuracy and reliability of the finite element simulation.It is concluded that at a certain cell height,the increase of the inclination angle and cross-sectional diameter of the support rod will improve the compression resistance of the multilayer dot matrix structure,and the influence of the inclination angle on the overall equivalent flat compressive strength of the structure is greater than that of the rod diameter;the relative density of the reinforced Kagome multilayer dot matrix structure cell is increased from 16.6% to 60.7%,the overall equivalent flat compressive modulus is increased by 5.54 times,and the maximum equivalent flat compressive strength is increased by 4.52 times.The relative density of reinforced Bcc multilayer dot matrix structure cells increased from 27.8% to 97.7%,and the overall equivalent compressive modulus increased by 4.78 times and the maximum equivalent compressive strength increased by 4.33 times.The overall relative specific strength and specific stiffness are related to the inclination angle and cross-sectional diameter of the cell element,and both are positively correlated;when the inclination angle of the support bar is small,the equivalent flat compressive modulus and the maximum equivalent flat compressive strength are less influenced by the diameter of the support bar,and as the angle of the support bar becomes larger,the effect of the support bar diameter on the equivalent flat compression modulus and the maximum equivalent flat compression strength also increases.In addition,in this thesis,the Kagome and Bcc reinforcement lattice structures are designed with lightweighting,cross-combination,and variable cell density.The lightweight design of the reinforcement plate reduces the overall mass of the lattice structure,and the compression simulation and experimental results show that the lightweight design slightly improves the equivalent flat compressive modulus,overall specific strength,specific stiffness,and energy absorption per unit mass of the lattice structure before compressive collapse failure;the cross-combination model inherits the compression and energy absorption characteristics of the Kagome and Bcc lattice structure,and the combination of different cell elements is strengthened at the interface is strengthened,the increase of B-layer will enhance the compression resistance of the combined structure,and the increase of k-layer will reduce the overall mass of the combined structure.During the compression process before the structure reaches densification,the energy absorption properties of the combined structure are all improved to different degrees relative to the original Kagome structure,in which the B-k-B lattice structure has the strongest energy absorption capacity per unit mass and is better than the original Bcc structure;the overall relative density of the lattice structure with variable cell element relative density is close to the overall relative density of the intermediate cell layer,and between the strain of 0.2 and densification,its the energy absorption capacity per unit mass is better than that of the uniform density dot matrix with the same parameters,so the anti-compression performance and excellent energy absorption capacity of the variable cell element relative density structure can be more fully utilized in different physical field of real engineering.