缺陷对金属蜂窝材料面内冲击性能的影响

 利用显式动力有限元ANSYS/LS-DYNA，数值研究了缺陷（胞元缺失）的分布位置及其尺寸对金属蜂窝材料面内冲击性能的影响。考虑到理想六边形蜂窝材料在不同冲击速度下的变形特征，将试件划分成9个子区域，讨论了缺陷集中位置、缺陷尺寸和冲击速度对蜂窝材料面内冲击变形模式和能量吸收性能的影响。研究发现，蜂窝材料的面内冲击性能依赖于缺陷的分布位置和缺陷尺寸，且在中低速时表现出较高的敏感性，但冲击速度的增加将弱化缺陷分布不均匀性的影响。由于缺陷的存在，蜂窝材料的能量吸收能力明显降低，但与缺陷分布位置相比，蜂窝材料单位体积所吸收的能量更敏感于缺陷尺寸。研究结果将为多胞材料的安全性评估及能量吸收设计提供理论指导和依据。

Effect of Defects in-Plane of Metal Honeycomb on Its Dynamic Impact Properties

The influence of defects on the dynamic performance of honeycomb is widely studied, but it is mainly focused on the effect of defect type and defect ratio, and the influence of defect distribution has not yet been fully developed. Effect of defect (the cell missing) distribution domain and its size on the in-plane dynamic impact properties of metal honeycomb was numerically investigated in this work based on explicit dynamic finite element simulation by ANSYS/LS-DYNA. Considering the deformation characteristics of perfect hexagonal honeycomb at different impact velocities, the specimen was divided into nine different sub-domains. Then, the influence of defect location, the size of single defect and the impact velocities on in-plane deformation modes and the energy absorption abilities of honeycomb were explored in detail. Results show that the in-plane dynamic impact properties of honeycomb depend on defect location as well as defect size. The dependence displays higher sensitivity especially at intermediate and lower impact velocities. With the increase of the impact velocity, the influence of defect location is weakened. Due to the existence of local defects, the in-plane energy absorption ability of honeycomb decreases obviously. However, comparing with the defect distribution, the absorbed energy per volume of honeycomb displays a higher sensitivity on the single defect size. The results potentially provide theoretical guides for the safety evaluation and energy absorption design of cellular materials.