Stiffness Optimization And Performance Research Of Honeycomb Structure With Negative Poisson’s Ratio

Since the concept of metamaterial was proposed in the early 21 st century,it has gradually become an important branch of new material technology after more than 20 years of development.Negative Poisson’s ratio metamaterials often have excellent properties such as light weight,impact resistance and heat insulation,so they are widely used in functional materials,and are often used in working conditions involving explosion,collision and impact.But most of the negative Poisson’s ratio materials have a lot of gaps and hinges in the microstructure,and their special deformation mode and geometry make the stiffness of negative Poisson’s ratio materials much lower than that of traditional solid materials.The stiffness determines the bearing capacity of negative Poisson’s ratio materials,and the low stiffness limits the engineering application of negative Poisson’s ratio materials to a certain extent.In view of this,this paper improves the stiffness of negative Poisson’s ratio material from three levels of size optimization,shape optimization and topology optimization to improve its static bearing capacity.Specifically,there are three aspects:Firstly,the stiffness of the concave ring honeycomb with good energy absorption effect is studied.The finite element models of the inner concave ring honeycomb and the inner concave hexagon honeycomb are established.Based on the linear finite element solver,the static simulation is carried out to obtain the equivalent elastic modulus of the inner concave ring honeycomb and the inner concave hexagon honeycomb and take it as the stiffness evaluation index.The results of experiment and simulation are in good agreement,which verifies the reliability of this study in the finite element modeling method.On this basis,the equivalent elastic modulus of the inner concave ring honeycomb and the inner concave hexagon honeycomb are compared,and the influence of some important size parameters on the stiffness of the inner concave ring honeycomb is analyzed.The results show that the stiffness performance of the inner concave ring honeycomb with good energy absorption effect is better than that of the inner concave hexagon honeycomb α and γ.The equivalent elastic modulus increases with the increase of the parameter β.The equivalent elastic modulus decreases with the increase of temperature.Secondly,based on the concave hexagonal honeycomb,a new type of stiffness optimization honeycomb is designed,and its related mechanical properties are explored.The finite element model of the new honeycomb structure is established,and the stiffness performance of the new honeycomb structure is compared with that of the concave hexagon honeycomb structure;The influence of key geometric parameters on the mechanical properties of the new honeycomb structure is analyzed;Aiming at the common impact conditions of honeycomb structure,a mixed material design strategy is proposed.The results show that the new honeycomb structure has better stiffness performance and negative Poisson’s ratio effect when the specific size parameters are selected;The negative Poisson’s ratio effect of the new structure can be further improved by the mixed material design for the impact condition.Finally,a new topology optimization formulation is proposed to design honeycomb structures with consideration of stiffness and negative Poisson’s ratio.The topology optimization formula is constructed by programming,and the clear topology optimization result is obtained.The topology optimization result is named as topology optimization concave honeycomb,and the feature extraction is carried out.The topology optimization concave honeycomb is tested and analyzed by finite element method to evaluate its stiffness performance.The influence of important size parameters on the stiffness performance of topology optimized concave honeycomb is analyzed by finite element simulation.The results show that the topology optimization concave honeycomb has superior stiffness performance,and the size analysis results have important reference value for its engineering application.