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.