Abstract:
Negative Poisson's ratio honeycomb structure has excellent mechanical properties including indentation resistance, impact resistance and energy absorption. In order to better study the mechanical properties of negative Poisson's ratio structure, this paper selects two kinds of negative Poisson's ratio structure: Anti-tetrachiral structure and re-entrant structure for comparative analysis. In order to improve the mechanical properties of honeycomb structure, polyurethane foam was filled in the structure. The deformation modes and mechanical properties of the foam-filled anti-tetrachiral structure and re-entrant structure were experimentally studied. In addition, through the parametric study of the foam-filled anti-tetrachiral structure, the effects of wall thickness
t and node radius
r on the energy absorption and Poisson's ratio of the structure were analyzed. The results show that the energy absorption and bearing capacity of anti-tetrachiral structure is better than that of the re-entrant structure. After filling the two kinds of structures respectively, the structure has higher stiffness and energy absorption, but the ‘auxetics’ effect is weakened. With the increase of wall thickness
t and node radius
r, the stiffness and energy absorption capacity of the foam-filled anti-tetrachiral structure increase, the Poisson's ratio increases, and the "auxetics" effect decreases. However, the brittle failure of the structure is enhanced and its specific energy absorption is weakened when the wall thickness is too thick. In addition, the compaction strain of the four-ligament backhand structure decreases with the increase of the wall thickness
t and the decrease of the node radius
r.