Mechanical Properties Of Negative Poisson's Ratio Honeycomb Structure With Variable Angular Concave Sides

Based on the existing circular honeycomb structure,a variable angular concave honeycomb structure with negative Poisson's ratio effect is proposed in this work.The bending internal forces of the rigid frame structure are analyzed and the analytical formulas of the transverse/longitudinal equivalent elastic modulus and the equivalent Poisson's ratio are obtained by using the energy method.The concave honeycomb structure proposed in this paper can be degenerated into the existing circular honeycomb structure.The present analytical solution is in agreement with the existing theoretical solution and finite element results,which shows validity of the present method.Based on the obtained analytic solution,the effects of the microstructure geometric parameters on the equivalent elastic modulus and equivalent Poisson's ratio are discussed.The results are theoretically important for guiding the structure design and mechanical properties of the honeycomb structures with negative Poisson's ratio.The in-plane dynamics analysis of the concave honeycomb structure with variable angular was carried out,and the numerical simulation was carried out by ANSYS/LS-DYNA finite element software.The deformation mode of the impact process of the concave honeycomb structure in the variable arc angle is analyzed,and the nominal stress-strain curve of the impact end is derived.According to the data of the nominal stress-strain curve,the bulk energy absorption rate and the platform stress of the concave arc-shaped concave honeycomb structure are calculated.The influence of the microstructure geometric parameters and impact velocity on the body energy absorption rate and the platform stress is discussed.The impact of the impact on the concave honeycomb structure with variable angular in different directions is studied.Compare the deformation mode,nominal stress-strain curve,energy absorption capacity per unit volume and platform stress of the impact process in different directions.The influence of different impact directions and the causes of different impact results are analyzed.The optimal solution of the energy absorptioneffect of the concave honeycomb structure with variable arc angle under different impact velocity and impact direction is discussed.