Research On The Out-of-plane Energy Absorption And Cushioning Performance Of Triangular Honeycomb Cores

Honeycomb structural materials are widely used in many fields such as cushioning packaging,aerospace industry,and construction,due to the excellent energy absorption and cushioning performance.As a typical polygonal honeycomb structure,the triangular honeycomb is often subject to the loadings in out-of-plane direction.The current investigations have well solved the out-of-plane cushioning performance of hexagonal and circular honeycomb structure materials.In this paper,the finite element simulation method is used to study the out-of-plane dynamic compression performance of triangular honeycomb based on the existing investigations,which is of great significance for the promotion of their applications.In this paper,the software of ANSYS/LS-DYNA is employed to create the finite element models based on the representative cell for the out-of-plane dynamic compression of triangular honeycomb cores.From the comparision between the analysis results based on this finite element model with the theoretical values,it is proved that the finite element model based on the representative cell is reliable.In comparision with the calculated results based on the finite model based on the cell array,it is further proved that the finite element model of triangle honeycomb cores based on the representative cell is reliable for the out-of-plane dynamic compression.Based on these,the effects of cell arrangement,compression velocity,and cell configuration parameters on the out-of-plane dynamic energy absorption and cushioning performance of triangular honeycomb cores are studied.Meanwhile,the out-of-plane energy absorption performances of regular hexagonal and triangular honeycomb are compared.For different cell arrangement,compression velocity,and cell configuration parameters,the out-of-plane deformation modes of triangular honeycomb cores are all in the form of top-down folds.The typical stress-strain curve includes four stages:linear elasticity,yielding,platform and densification,and the curve of energy efficiency firstly increases and then decreases with the increase of strain.The cell arrangement pattern has no effect on the energy absorption and cushioning performance of the triangular honeycomb cores with fixed cell configuration parameters under a given compression velocity.For a given compression velocity,the out-of-plane energy absorption of regular triangle honeycomb cores are larger than that of regular hexagonal honeycomb,and both increase with the increase of compression velocity.For each cell arrangement of triangular honeycomb cores,the out-of-plane initial peak stress,dynamic plateau stress,and specific energy absorption increase with increasing compression velocities,and the minimum cushion coefficient decreases with increasing compression velocities.For a given compression velocity,the out-of-plane initial peak stress,dynamic plateau stress,specific energy absorption and the minimum cushion coefficients of triangular honeycomb cores with a fixed expansion angle,all increase with the increase of the ratio of cell wall thickness to edge length.When the compression velocity is fixed,the out-of-plane initial peak stress,dynamic plateau stress,specific energy absorption and minimum cushion coefficient of triangular honeycomb cores with a fixed ratio of cell wall thickness to edge length,decrease first and then increase with the increase of expanding angle.The correlations between them and expanding angle can be well fitted by certain curves,and the corresponding empirical formulas are given based on the calculated results.