Modelling, experimental characterization and design optimization of honeycomb sandwich plates with three-dimensional printed halloysite nanotube-reinforced core material and carbon nanotube-reinforced face sheets

Abstract

This study presents an integrated experimental, modelling and computational investigation of the effects of halloysite nanotubes (HNTs) and carbon nanotubes (CNTs) on the weight-minimized design of hexagonal honeycomb sandwich plates subjected to compressive loading. An ABS-like resin reinforced with HNTs was fabricated using three-dimensional (3D) printing for core material characterization, while carbon/epoxy face sheets enhanced with CNTs were produced via hand lay-up. Standard tests were performed to determine the optimal nano-additive contents and to characterize the mechanical properties of the constituent materials. The results showed that 0.3 wt% HNTs maximized the Young’s modulus of the printed resin, whereas 0.5 wt% provided the highest compressive strength. For the laminated face sheets, 0.3 wt% CNTs significantly improved stiffness and strength. The experimentally obtained material properties were subsequently incorporated into an analytical modelling framework to evaluate the buckling response and fundamental natural frequencies of idealized hexagonal honeycomb sandwich plates. Multiple failure criteria and frequency constraints were integrated into a computational optimization procedure aimed at minimizing structural mass. The results indicate that geometric design parameters strongly influence the effectiveness of nano-reinforcement in lightweight sandwich configurations, and mass reductions of up to 75 % were achieved depending on the imposed optimization constraints.