Comparison Of In-plane Impact Deformation And Energy Absorption Characteristics Of Aluminum Honeycomb Material With Wall Thickness Gradient

Multicellular metals have been widely used in the fields of collision energy absorption protection devices and aerospace due to their excellent properties of light weight,high strength,energy absorption,sound insulation and heat insulation,and their typical representative is the uniform honeycomb aluminum material.With the deepening of this research field and the diversified demands of the engineering field,it is difficult for a single uniform honeycomb material to meet the higher requirements for use.The gradient porous material is gradually emerging in order to obtain the ideal honeycomb material with low stress peak and long platform section.In this dissertation,the finite element software ANSYS/LS-DYNA was used to establish a uniform honeycomb aluminum material model,and the reliability of the model was verified.Then the deformation and energy absorption of two types of honeycomb aluminum materials at two speeds were simulated.In order to understand its deformation and energy absorption mechanism more intuitively,a monocytocyte finite element model was established for comparison,and the conclusion was drawn that the energy absorption effect of uniform honeycomb material increased with the increase of impact velocity.In addition,the energy absorption effect of uniform honeycomb material in the direction of X₁was better,while the energy absorption in the direction of X₂ was better under the same velocity comparison.Based on the aforementioned uniform honeycomb model,the gradient is changed again by changing the arrangement and combination of the three wall thicknesses.The deformation mode,dynamic response of the impact end and the dynamic response of the fixed end at different speeds and different thickness combinations are studied.The concept of the absolute value of density change is used to explain the law of the change of the magnitude of the stress peak,and the lengths of the platforms corresponding to several models are compared.Finally,the energy absorption efficiency of several honeycomb specimens with different speeds and different thickness combinations is comprehensively compared through finite element and traditional theoretical methods.It is concluded that the overall performance of gradient honeycomb energy absorption is better than that of uniform honeycomb,and as the speed increases,the energy absorption efficiency increases,and the energy absorption effect in the X₁ direction under the same thickness gradient arrangement is more ideal.In both directions,the energy absorption under high-speed impact will be divided into two stages.The first half is the best energy absorption efficiency of S321.When the compression process reaches nearly 60%,a turning point will appear.After this point,the energy absorption efficiency of S213 becomes the highest.It provides some references for the design of gradient honeycomb materials and the optimized design of energy absorption.