Blast performance of shear thickening fluids filled auxetic honeycomb sandwich beams

Although considerable progress has been achieved in impact resistance of shear thickening fluid (STF)-filled honeycomb structures, research on their blast performance remains relatively scarce, with a notable lack of reliable experimental data. In this paper, the blast performance of STF-filled auxetic honeycomb sandwich beams (AHSBs) is investigated by experimental and numerical approach. The dynamic response of STF under high-strain-rate conditions is first characterized through the split Hopkinson pressure bar (SHPB) tests. Three constitutive models for STF (power-law, Johnson-Cook and visco-hyperelastic) are compared and validated in numerical simulations of SHPB tests. Numerical simulations indicate that the visco-hyperelastic model most accurately represents the dynamic behavior of STF under high-strain-rate impact. Subsequent blast experiments and corresponding numerical analysis examine the effect of STF filling on the dynamic response of AHSBs. Experimental results demonstrate that the STF-filled AHSB exhibits significantly improved blast resistance relative to the unfilled AHSB, with 23.57% smaller residual midspan displacement and reduced local damage. Numerical results further indicate that STF filling increases structural flexural stiffness and promotes stress dispersion. Despite these advantages, the STF-filled AHSB exhibits a 20.58% lower specific energy absorption (SEA) than its unfilled counterpart. Consequently, STF is selectively introduced into critical cells to improve SEA while preserving the overall bending resistance of the structure. This work advances the application of STFs in honeycomb-based lightweight structures for blast resistance.