| description abstract | Double arrowhead honeycombs (DAHs) are a type of auxetic materials, i.e., showing negative Poisson's ratio (NPR), and are promising for energy absorption applications. Their inplane impact responses are theoretically and numerically explored. Theoretical models for the collapse stress under quasistatic, lowvelocity, and highvelocity impacts are developed, based upon the corresponding microstructural deformation modes. Obtained results show that the collapse stress under quasistatic and low velocity impacts depends upon the two reentrant angles responsible for NPR, while it is insensitive to them under highvelocity impact. The developed theoretical models are employed to analyze the energy absorption capacity of DAHs, showing the absorbed energy under highvelocity impact approximately proportional to the second power of velocity. Extension of the highvelocity impact model to functionally graded (FG) DAHs is also discussed. Good agreement between the theoretical and finite element (FE) predictions on the impact responses of DAHs is obtained. | |
