Topological study about failure behavior and energy absorption of honeycomb structures under various strain rates

Abstract

High-speed impact threats and terrorist actions on the battlefield require the development of more effective protective materials and structures, and various protective structure is designed according their energy-absorbing characteristics. In this research, the deformation behavior, microscopic failure modes and energy absorption characteristics of re-entrant hexagonal structure, regular hexagonal structure and regular quadrilateral structure are studied under different strain rates impact. The re-entrant hexagonal structure forms a “X”-shaped deformation zone, the regular quadrilateral and regular hexagonal structure form an “I”-shaped deformation zone. The microscopic appearance of the section is a mixed fracture form. The effects of the topological shape, cell angle, and cell height on the impact behavior of the structure were evaluated. When the cell height is fixed and the cell angle is changed, the energy absorption of the structure increase and then decrease as the relative density increase. The mechanical properties of the structure are optimal when the relative density is about 18.6% and the cell angle is 22.5°. When the cell angle is fixed and the cell height is changed, as the relative density increases, the energy absorption of the structure gradually increases. The regular quadrilateral structure and the re-entrant hexagonal structure experienced clear strain rate effects under dynamic impact conditions; the regular hexagonal structure did not exhibit obvious strain rate effects. The results presented herein provide a basis for further rational design and selection of shock-resistant protective structures that perform well in high-speed impact environments.

Keywords

• Honeycomb structures
• Impact loading
• Negative Poisson's ratio
• Titanium alloy
• Dynamic response