Dynamic responses of shear thickening fluid-filled lattice structures

Abstract

Lattice structures that possess exceptional energy absorption capabilities show promise across various fields. However, their tendency to exhibit relatively lower stiffness due to rotation or bending during impacts poses a challenge. Shear thickening fluid with the unique property of shear thickening effect can be an ideal filler to overcome the limitation of lattice structure. In this paper, composites that combined STF with new lattice structures were fabricated to investigate their dynamic response using experimental and numerical means and found that incorporating STF into these lattice structures not only preserved the inherent mechanical characteristics of the lattice structures but also led to substantial improvements on mechanical performance. The lattice structures displayed a noteworthy boost in stiffness, increasing significantly from 11.02 to 85.56 times. Additionally, there was an improvement in energy absorption, ranging from 2.78 to 5.51 times. These findings indicate that STF holds more promise in enhancing a structure's stiffness compared to its energy absorption capacity. Moreover, strain rate, weight fraction of STF, and cell size of the lattice structure were considered to further investigate their impact on the dynamic behaviour of STF-filled lattice structures. Our findings indicate that the increase in stiffness and energy absorption of the lattice structure following STF filling is correlated with an increase in strain rate and weight fraction but decreases when the cell size of the lattice structure is increased. The critical strain rate of STF-filled lattice structure was predicted, around 104 s−1, which indicates the onset of the shear-thickening effect in STF. Furthermore, it was observed that composites with higher weight fractions of STF were more responsive to changes in strain rate. Additionally, structures with initially lower mechanical properties experienced the most significant improvements after being filled with STF. These optimal outcomes provide valuable insights for the design of STF-filled lattice structures in practical applications.