Dynamic compressive behaviour of shear thickening fluid-filled honeycomb

Shear thickness fluid (STF) is considered an ideal filler to enhance the mechanical behaviour of in-plane honeycomb due to its special rheological properties. In order to investigate the dynamic compressive behaviour of STF-filled honeycomb, a comparative study between a STF-filled honeycomb and an empty honeycomb is numerically carried out after the fluid-structure coupled model has been validated against experimental testings. It is shown that the addition of STF in the honeycomb cells results in significant improvement in the energy absorption of the STF-filled honeycomb, which in turn, effectively prevents the premature collapse of the honeycomb cell walls. Furthermore, a parametric study of STF-filled honeycomb is conducted to investigate the contributions of each component to the total energy. It is found that the honeycomb plastic deformation is the predominant mechanism of energy absorption during impact, whilst the proportion of viscous energy contribution to the total energy is significantly reduced when the honeycomb wall thickness is increased. Additionally, the mean crushing force of STF-filled honeycomb has a power law relation to the honeycomb wall thickness for each specific loading velocity. Moreover, the mean crushing force contributed by STF is proportional to loading velocity and the increase in velocity significantly improves the percentage of viscous energy to the total energy. Meanwhile, optimal honeycomb thickness and weight fraction of STF are crucial to avoid earlier plastic densification of the honeycomb during the loading process. The results of this paper provide useful insights for future design and optimization of STF-filled structures.