In-Plane Dynamic Mechanical Response of Auxetic Hexagonal Honeycomb under Oblique Impact

The in-plane dynamic mechanical response of the auxetic hexagonal honeycomb under different impact angles, ranging from 0°–10°, and different impact speeds, ranging from 6–100 m/s, is systematically studied based on the corresponding numerical model. A novel formula is adopted for the cross-section to reflect the change of contact area between honeycomb structure and impact plate during oblique impact. The formular can reflect the change of stress from local region to whole model in the impact process well and capture the initial peak stress of honeycomb structure effectively. The results show that the auxetic structure has different deformation modes under oblique impact and axial impact, exhibiting local deformation under low-speed oblique impact, overall deformation under medium-high speed oblique impact, and overall deformation under axial impact. Compared with the regular hexagonal honeycomb structure, the auxetic structure is affected by the negative Poissonʼs ratio effect. Under the same loading condition, the deformation mode of the auxetic honeycomb deforms later than the regular hexagonal honeycomb structure does, exhibiting a delayed mode. In addition, focusing on the energy absorption historical curve, the plateau stress under the two calculation methods of cross-section area is compared and analyzed, which provides a basis for investigating the load-bearing and stability of honeycomb structures under oblique impact.