| The honeycomb structure originated from bionics.Inspired by the regular hexagonal honeycomb structure,its topological structure also gradually emerged,such as triangle structure,rectangle structure,five-pointed star structure,etc.With the deepening of research,scholars are not limited to simple topological structure,but add functional gradient honeycomb structure for exploration.Because honeycomb structural materials have the advantages of light weight,good stability,cushioning and energy absorption,they have a wide range of applications in the fields of construction,automobile,aerospace and so on.Therefore,it is of great significance to design and study honeycomb structures with better mechanical properties.In this paper,based on the construction of a new type of composite honeycomb structure with internal concave hexagon and star honeycomb structure,the deformation mode,mechanical properties and energy absorption effect of composite honeycomb structure and gradient honeycomb structure were studied by ANSYS/LS-DYNA finite element software simulation.The research results have enriched the basic theory of honeycomb structure materials.The main research contents are as follows:(1)Under the support of the homogenization theory,the direct homogenization method and the two-scale model progressive expansion method were organically combined to establish the stress-strain relationship between the macrostructure and meso-structure of honeycomb materials.The finite element software was used to analyze the model effectiveness in three directions: grid division,cell number and deformation mode.(2)The in-plane dynamics analysis of the new composite honeycomb structure was carried out,and the finite element software ANSYS/LSDYNA was used for simulation.The deformation mode at the impact velocity of 3m/s,7m/s,10m/s,30m/s and 70m/s and the deformation mode at the wall thickness of honeycomb structure of 0.12 mm,0.24 mm,0.37 mm and 0.50 mm were analyzed,and the stress-strain curve at the impact end was derived.Based on the stress-strain curve,the platform stress and energy absorption efficiency of the composite honeycomb structure were calculated,and the effects of impact velocity and structural wall thickness on the impact resistance and energy absorption efficiency of the composite honeycomb structure were discussed.(3)The in-plane impact mechanical properties of the gradient honeycomb structure were analyzed,the gradient rate γ was 0.0759 and 0.1521,and the number of honeycomb structure layers was 3 and 4,to explore the impact results of the positive gradient combined honeycomb structure and negative gradient combined honeycomb structure simulation.By comparing the deformation failure causes,stress-strain relationship and energy absorption performance of the combined honeycomb structures with different gradient rates and different layers,the results show that the gradient honeycomb structures have better impact resistance and energy absorption effect than the conventional honeycomb structures.The impact resistance of honeycomb structure with gradient rate of 0.1521 is better than that of honeycomb structure with gradient rate of 0.0759.The number of layers has little effect on the deformation mode of honeycomb structure.The impact resistance of positive gradient honeycomb structure is better than that of negative gradient honeycomb structure,and the energy absorption effect of negative gradient honeycomb structure is better than that of positive gradient honeycomb structure.Figure [39] table [6] reference [65]... |
