Optimized Design Of Enhanced Honeycomb Topology And Study On Mechanical Behavior Of Large Deformation

Biomimetics is an important source of many innovative structural designs,among which the honeycomb structure derived from the natural world is widely used in various fields such as aerospace,transportation,product packaging,construction,military protection and other fields because of its low density,high strength,high specific stiffness,impact resistance,and excellent energy absorption capacity.Under the demand for green energy conservation and lightweight design innovation,the design of honeycomb structures with stronger energy absorption characteristics has become a research hotspot.In the past,improving the energy absorption of honeycomb structures was mainly achieved through layered design,new biomimetic design,and gradient design.In recent years,it has been found that the addition of reinforcement grille to the honeycomb cells can improve the structural mechanical properties.Therefore,it is of great engineering significance to systematically explore the influence of adding different types of reinforcement grille on the mechanical properties of honeycomb structures and explore the preparation methods of complex honeycomb structures.The hexagonal honeycomb is enhanced by adding different types of grilles and performing rotation-optimized design in the regular hexagonal honeycomb.Aluminum honeycomb structure specimens are prepared using 3D printing technology,and quasi-static compression tests were carried out to detect investigate the influence of different topological configurations on the mechanical properties of honeycomb structures.The research results show that the finite element analysis and experimental results are in good agreement,and the in-plane performance of honeycomb structure can be studied by appropriately shortening the length of the finite element model in the out-of-plane direction to improve the finite element calculation efficiency.The enhanced honeycomb specimen first undergoes layer-by-layer crushing deformation,and then the structure collapsed as a whole.The stress-strain curve no longer exhibits the phenomenon of wave peaks and valleys,and the plateau segment curve is smoother.Finite element analysis is conducted on the enhanced honeycomb structure under quasi-static and dynamic compression in different in-plane directions.It is found that under quasi-static compression,the enhanced honeycomb structure can undergo a desirable layer-by-layer crushing deformation.Under dynamic compression,as the compression rate increases,the plastic deformation band of the honeycomb structure becomes more compact.Adding reinforcement grille significantly improves the plateau stress and specific energy absorption of the honeycomb structure.The optimization effect of the enhanced structure in the transverse direction within the plane is significantly higher than that in the direction of the strip within the plane.The out-of-plane mechanical properties of the enhanced honeycomb structure were studied,and a comparative analysis was carried out on the mechanical differences between the enhanced honeycomb structure and the regular hexagonal honeycomb structure.It was found that the progressive folding process of the enhanced honeycomb structure was more stable,the half-wavelength of the structural deformation was shortened,the plastic strain concentration area increased,and the structural bearing capacity was enhanced.The specific energy absorption of different honeycomb structures continuously increased with the relative density of the honeycomb structure.Based on the simplified super-folding element theory(SSFE)and simulation data,a theoretical formula that can accurately predict the compressive strength of the enhanced honeycomb structure was established.According to the different compressive strength of the enhanced honeycomb structure,the concept of layered gradient honeycomb structure is proposed,and the influence of the introducing gradient design on the in-plane mechanical properties of the honeycomb structure is studied.It is found that under low-speed compression,the gradient honeycomb structure undergoes sequential crushing from the layer with the lowest strength to the highest,and the mechanical response curve shows obvious segmented characteristics.As the compression speed increases,the deformation mode gradually changes from sequential crushing from the impact end to the fixed end,and the segmented characteristics of the mechanical response curve gradually disappear.The gradient honeycomb structure can effectively reduce the initial peak stress of the structure,and adjusting the gradient change in the medium and high-speed compression state can effectively control the energy absorption capacity per unit mass of the structure.