Research On Mechanical Properties Of Negative Poisson's Ratio Structural Parts Based On 3D Printing

In recent years,the research and application of negative Poisson's ratio structure has been a hot topic in the scientific research.Negative Poisson's ratio structure has the advantages of good energy absorption and good thermal insulation,and is widely used in aviation,transportation and medical fields.3D printing has the advantages of rapid prototyping and personalized manufacturing,which can realize the rapid preparation of negative Poisson's ratio structures.Based on the 3D printing processing method of Fused Deposition Modeling(FDM),this dissertation deeply studies the mechanical properties of negative Poisson's ratio structure,and provides theoretical guidance and ways for the optimization,improvement and popularization of negative Poisson's ratio.The research content of the paper is as follows:(1)Theoretical analysis of the mechanical properties of negative Poisson's ratio(NPR)structure.The mechanical properties of negative Poisson's ratio(NPR)structure are analyzed by establishing a mechanical model of negative Poisson's ratio(NPR)structure.The effects of different structural parameters(wall thickness t,angle ?)on the equivalent elastic modulus,shear modulus and Poisson's ratio of NPR structures are analyzed.(2)The concept of equivalent density is introduced to study the mechanical properties of different types of honeycomb structures at the same equivalent density.Negative Poisson's ratio(NPR)structure,triangular(TRI)honeycomb structure,rectangular(RECT)honeycomb structure and hexagonal(HEX)honeycomb structure are designed and manufactured,and mechanical experiments of the above four structures are carried out.The experimental data are analyzed according to the evaluation indexes of energy absorption(total energy absorption W,mass specific energy absorption SEA and volume specific energy absorption S).The results show that the negative Poisson's ratio(NPR)structure has the best energy absorption.(3)The influence of the material types(PLA,TPU)and structural parameters on the mechanical properties of 3D printed negative Poisson's ratio structure are studied.The negative Poisson's ratio structural specimens are designed and manufactured to carry out compression experiments.The elastic modulus E of PLA and TPU specimens are obtained by analyzing the experimental data according to the evaluation index of energy absorption.The experimental results are consistent with the theoretical derivation and verify the correctness of the theoretical derivation.With the increase of wall thickness t,the energy absorption of PLA and TPU specimens is gradually enhanced.The energy absorption of PLA and TPU specimens decrease with the increase of angle ?.When wall thickness t=3mm and angle ?=-40°,the negative Poisson's ratio(NPR)structure has the best buffer energy absorption.The energy absorption of TPU material is better than PLA.The application of negative Poisson's ratio structure is realized based on the advantages of 3D printing and personalized manufacturing.