Study On Large Deformation Mechanical Behavior Of Multilayer Gradient Aluminum Honeycomb Panel

The hexagonal honeycomb sandwich panel is a high-strength,low-density,lightweight structure,and it has been proven to have excellent impact resistance and energy absorption characteristics,so it has a wide range of uses in many fields.However,a large amount of research is currently focused on single-layer aluminum honeycomb sandwich panels and multilayer composite m aterial sandwich panels.Relatively little research has been done on multilayer and multi-gradient aluminum honeycomb sandwich panels,which has seriously hindered its application in aerospace,rail and automobile industry.Thus,it is of great significanc e to carry out research on multilayer gradient aluminum honeycomb sandwich panels.In this paper,experimental and finite element simulations of bonded gradient honeycomb sandwich panels are performed the flattening under quasi-static,the flat punch under impact and the drop impact,respectively.The study found:During the quasi-static compression process,the larger the gradient rate is,the smaller the buckling load of the aluminum honeycomb sandwich panel is and the more obvious the layer compaction phenomenon is.The deformation sequence of the honeycomb core is preferentially low density until compaction.The compaction strain difference between the layers gradually decreases with the increase of the core layer density,and under the same displacement of the pressure head,it has less energy absorption.In the high-speed flat punching state,the gradient aluminum honeycomb sandwich panel is not deformed step by step in the quasi-static process until it is compacted.It is the linear elastic deformation,elastic buckling,plastic collapse,and compaction that occur under the interaction of the impact inertia of the impact plate and the core layer density.In addition,the peak impact load of gradient honeycomb sandwich panels with different gradient rates is related to the density of the core layer at the impact end.The higher the density of the core layer at the impact end,the higher the peak impact load that the honeycomb sandwich panel can bear.At the same time,through experiments and simulation studies,it has been proved that the gradient design of the honeycomb sandwich plate can improve its energy absorption capacity in the early stage of impact.The gradient rate designed in this paper shows that when the gradient rate is?₁=0.0276,the energy absorption of the gradient honeycomb sandwich panel is the best.Compared with the homogeneous honeycomb sandwich panel with the same mass,the energy absorption is increased by 10.63%.Under the impact of a falling hammer,when the quality and gradient rate of the honeycomb sandwich panel are the same,the influence of the impact speed on the energy absorption of the gradient honeycomb sandwich panel is mainly reflected in the change rate of the energy absorption.The larger the impact velocity is,the l arger the energy absorption change rate of the gradient honeycomb sandwich panel is in the initial stage,but the total energy absorption effect on the gradient honeycomb sandwich panel test piece is small.Besides,when the quality of the honeycomb sandwi ch panel and the impact speed are constant,the gradient rate has a crucial impact on the energy absorption of the honeycomb sandwich panel.But it no longer blindly follows the rule that the honeycomb sandwich panel has better energy absorption as the gra dient rate increases under the flat punching state.And as the impact angle decreases,the separation between the honeycomb core layer and the panel becomes more obvious.In addition,the change in the path of the hammer head through the core layer has lit tle effect on the energy absorption of the honeycomb sandwich panel,and the failure mode of the panel is the effect.The main reason for energy absorption of gradient honeycomb sandwich panels.