In-plane Dynamic Crushing Of Functionally Graded Metal Honeycombs

Due to their particular characteristics, the prospective application of porous materials has attracted more and more attention. How to accurately describe the dynamics properties of porous materials has become one of the hot topics. Referencing to the concept of functionally graded materials, one kind of functionally graded circular honeycombs (FGCH) are established. By gradually changing the cell radius or wall thickness along one or more directions, the in-plane characteristic parameters of honeycombs become controllable, which provides the possibility to realize the multi-objective optimal design of materials.Based on this model, nonlinear finite element software ABAQUS was used in our research. The relation between the dynamic responses of FGCHs and the impact velocities, gradient coefficients, as well as cell packing pattern, is discussed. Through a series of comparative study, we assert that:(1) FGCH shows step deformation characteristic. Under the low velocity impact, the plateau stress increases with the compression of the materials; while along with the increase of the impact velocity, for thickness variation FGCH when a<0, or radius variation FGCH when a>0, the plateau stress decreases along with the compression of the materials;(2) A weak layer (layer with big radius or thin wall) near the impact end can effectively reduce the initial stress peak;(3) Under the low velocity impact, for the same structure, the influence of the impact direction (i.e. the sign of the gradient coefficient a) can be ignored. But with the increase of the impact velocity, by changing the value and sign of the gradient coefficients, the energy absorption could be effectively controlled.(4) In a limit geometric dimension, through the filling of FGCHs in structures, the energy absorption ability is increased combined with the control of the initial force peak.