Experimental and numerical study on the energy dissipation behavior of carbonyl iron powder/shear-thickening composites under high-energy impact

Shear-thickening materials exhibit rate-dependent mechanical responses. However, their intrinsic physical characteristics and dynamic performance under high-energy impact loading remain insufficiently studied. To address this knowledge gap, this work systematically examines material preparation, custom equipment design, and numerical simulations using LS-DYNA. The results show that optimal energy dissipation is achieved with a mass ratio of polydimethylsiloxane to pyroboronic acid (PA) α = 0.3 and a mass ratio of carbonyl iron powder to the shear-thickening matrix β = 1.2. A dedicated drop-hammer testing apparatus was designed and fabricated, allowing adjustable impact energies ranging between 50 and 600 J. By integrating experimental tests with LS-DYNA simulations, this study characterizes the energy dissipation behavior of both the entire test setup and the carbonyl iron powder-reinforced shear-thickening material under drop-hammer impact. The device dissipates 60%–80% of the total impact energy, with the overall energy dissipation rate increasing monotonically with impact velocity. At the material level, energy dissipation rises with sample thickness, as does the proportion of total energy absorbed by the material. Under the conditions of an impact velocity of 7.00 m/s and a sample thickness of 9.9 mm, the material exhibits a maximum uniaxial elongation of 7–8 times its original length. At a fixed impact energy, the overall dissipation rate increases with increasing velocity, whereas the intrinsic dissipation rate of the material decreases. Compared with conventional rubber, the composite shear-thickening material demonstrates pronounced rate sensitivity and a superior, rate-tunable energy absorption capability.