Study On Impact Mechanical Properties Of Concave Hexagonal Honeycomb Structures

Because porous materials have the advantages of small mass,high strength and specific stiffness,and good stability,porous materials or honeycomb materials are widely used in the field of national defense,energy and chemical industry,which focuses on ship side protection and aerospace.With the deepening of research on materials and the improvement of performance requirements,leading scholars in the field of materials turn their attention to honeycomb materials with special properties.At this time,honeycomb materials with negative Poisson's ratio effect emerge at the historic moment.With the development of research,ordinary uniform honeycomb can no longer meet the pursuit of high performance materials,at this time,functional gradient materials become the current hot.In this paper,ABAQUS finite element software is used to investigate the impact mechanical properties of homogeneous cells with concave hexagonal cells and angular gradient cells with negative Poisson's ratio effect under two pressing directions and the impact mechanical properties of layered gradient cells with different yield strength under four different arrangements.Main work contents:The dynamic response of honeycomb materials with concave hexagonal cells and negative Poisson's ratio effect under two pressing directions is simulated by software.The effect of deformation,stress-strain curves and energy absorption on the homogeneous concave hexagonal honeycomb structure at two pressing directions(X1 and X2 directions)and three pressing speeds was investigated.The mechanical properties of honeycomb materials with negative Poisson's ratio effect in different pressing directions were revealed by comparing the dynamic properties of honeycomb materials with negative Poisson's ratio effect in different pressing directions.On the basis of uniform honeycomb structure,the concept of functional gradient honeycomb is introduced.By changing the Angle between oblique rib and horizontal rib of concave hexagonal cell,a calculation model of angular gradient honeycomb material is constructed.The angular gradient cells with concave hexagonal cells were simulated by software under three different impact velocities and two pressing directions(X1 and X2directions).The material deformation,dynamic response and specific energy absorption of the angular gradient cells under different pressing directions were analyzed.With the rise of composite materials and many uncertainties in manufacturing process,layered negative Poisson's ratio honeycomb is also a hot research topic today.The cell structure with concave hexagonal layer and negative Poisson's ratio is composed of aluminum substrate with different yield strength.The dynamic characteristics under four arrangements and three impact velocities were studied,and the differences in deformation modes,stress-strain curves and energy absorption characteristics under four arrangements were compared and analyzed.According to the simulation results of the finite element software and the post-processing of the software data,the initial stress peak of the honeycomb material with negative Poisson's ratio effect is lower than that of the conventional honeycomb material with regular hexagonal cells,but the overall compressive strength of the structure is greatly improved,and the energy absorption capacity of the material is also improved.The mechanical properties of functionally gradient honeycomb structure model are affected by many factors,such as the Angle of concave hexagonal structure,stamping direction and stamping speed.The ability of layered negative Poisson's ratio honeycomb structure to protect components is also improved compared with ordinary honeycomb materials.Therefore,the honeycomb materials with gradient and layered honeycomb materials have a very broad prospect in the field of buffer materials.