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In the present study, a 2D-based large-scale metallic auxetic double arrowhead honeycomb core sandwich panel (DAHSP) was proposed and its deformation response, energy dissipation characteristics and associated mechanisms under air blasts were investigated using a validated numerical model. It aims at the performance improvement of DAHSPs through the design of core relative density with respect to different strategies. The DAHSPs considered mainly experienced a local dome superimposed upon global deformation of front face and global deformation of back face, while the core webs were heavily buckled and progressively collapsed. The results confirmed the material concentration effect of DAH cores induced by the negative Poisson’s ratio (NPR). It was found that the panel deformation response was highly related to their deformation/failure mechanisms. Relative to core web thickness, the increase of number of core layers led to a more remarkable decrease in permanent deflections. However, the decline of inclined angles not always reduced the back face deflection due to the competition between enhanced bending stiffness and deteriorated local contact force. An ideal means to decrease the panel deformation is to enlarge the inclined angles at low relative density but to decrease the horizontal distance when the relative density increases to a high level. The panel with thinner core webs at low relative density and the panel with narrowed inclined angles at high relative density is more beneficial to plastic energy absorption. In addition, a core configuration with a thinner tendon but a thicker stuffer promoted the exploitation of NPR and further improved the panel energy absorption.

This research aims to improve the blast performance of trapezoidal corrugated core sandwich panel under air blast loading. A finite element model for the prediction of dynamic responses of trapezoidal corrugated core sandwich panel was first proposed and validated by experiments. Based on the simulation results, kriging models were established to approximate the relationships between design variables and blast performances, and correlation analyses were carried out to investigate the effects of the design variables on the maximum back face deflection and specific energy absorption. It is found that any decrease in maximum back face deflection would always lead to undesirable deterioration in specific energy absorption, and the correlation relationships are associated with the stand-off distance. Using the developed kriging models, multi-objective design optimization was performed to seek trade-off solutions for the trapezoidal corrugated core sandwich panel under specific and variable stand-off distances. Results show that the design on Pareto fronts depended upon stand-off distance. Comparisons of the blast performance between optimized designs and initial designs turned out that there indeed existed a great potential in performance improvement. Importantly, careful examination of the responses of the optimized designs revealed some valuable design methods which should be useful for the engineering applications of trapezoidal corrugated core sandwich panel.