Blast performance of 3D-printed auxetic honeycomb sandwich beams

Little research has been conducted on comparing the blasting characteristics between the regular hexagonal and auxetic honeycomb sandwich beams (RHSBs and AHSBs). To address this gap in knowledge, the study utilised both experimental and numerical analyses. The HSBs consisted of steel top and rear face sheets bonded to a stainless- steel honeycomb core. The parameters considered in this test included the core configuration (regular vs. auxetic hexagonal) and face-core bonding method (adhesive vs. integrated). Results revealed that at scaled distances of 0.8617 m/kg^1/3 and 0.7971 m/kg^1/3, the AHSB core exhibited a reduction in mid-span displacement of only 3.3 % and 3.7 %, respectively, compared to the RHSB core. However, the compression value of the AHSB core significantly exceeded that of the RHSB core by 171.5 % and 161.5 %, respectively. This finding indicates that auxetic honeycomb cores possess enhanced energy absorption capacity to withstand blast loading. In addition, using unbonded face sheets increases the range of local cell deformation and decreases the global flexural bending by 22.66 % and 24.14 % at scaled distances of 0.8617 m/kg^1/3 and 0.7971 m/kg^1/3, respectively, compared to the AHSBs with face sheet debonding. To further investigate the damage mechanism of HSBs subjected to blast loading, a well-validated finite element model was employed. Notably, parametric simulations demonstrated that the dynamic behaviour of AHSBs under blast loading is significantly influenced by cell wall thickness, face sheet thickness, and cell angle.