Dual-level stress plateaus in honeycombs subjected to impact loading: perspectives from bucklewaves, buckling and cell-wall progressive folding
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Dual-level stress plateaus (i.e., relatively short peak stress plateaus, followed by prolonged crushing stress plateaus) in metallic hexagonal honeycombs subjected to out-of-plane impact loading are characterized using a combined numerical and analytical study, with the influence of the strain-rate sensitivity of the honeycomb parent material accounted for. The predictions are validated against existing experimental measurements, and good agreement is achieved. It is demonstrated that honeycombs exhibit dual-level stress plateaus when bucklewaves are initiated and propagate in cell walls, followed by buckling and progressive folding of the cell walls. The abrupt stress drop from peak to crushing plateau in the compressive stress versus strain curve can be explained in a way similar to the quasi-static buckling of a clamped plate. The duration of the peak stress plateau is more evident for strain-rate insensitive honeycombs.
KeywordsHoneycomb Impact loading Dual-level stress Strain-rate sensitivity
This work was supported by the National Natural Science Foundation of China (Grants 11472209 and 11472208), the China Postdoctoral Science Foundation (Grant 2016M600782), the Postdoctoral Scientific Research Project of Shaanxi Province (Grant 2016BSHYDZZ18), the Zhejiang Provincial Natural Science Foundation of China (Grant LGG18A020001), the Fundamental Research Funds for Xi’an Jiaotong University (Grant xjj2015102), the Jiangsu Province Key Laboratory of High-end Structural Materials (Grant hsm1305), and the Natural Science Basic Research Plan in Shaanxi Province of China (Grant 2018JQ1078).
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