Shear-thickening-fluid-based meta-material for adaptive impact response.

Lattice and Triply-Periodic-Minimal-Surface (TPMS) structures are widely employed in different engineering disciplines, combining interesting designs with optimal mechanical properties thanks to the capabilities of Additive Manufacturing. In this framework, a technique based on filling a 3D-printed flexible structure with a shear-thickening fluid (STF) is proposed to improve the mechanical response of the resulting bi-phase composite under impact loads in the low-velocity regime up to around 3 m/s. Test data indicate that once the critical shear rate threshold for the fluid is reached, the STF-filled structure can effectively smooth the peak acceleration by 50%, decrease the penetration depth and significantly enhance the energy absorption capability by a remarkable 85%. The proposed hybrid composite paves the way to novel functional applications, exploiting the adaptive behavior of non-Newtonian fillers. To this end, a Finite-Element model is proposed to further investigate and optimize the underlying fluid-structure interaction responsible for improvement of the dynamic compressive response. • STF-filled metamaterial shows a 50% reduction in peak acceleration and a 85% enhancement in the energy absorption capability. • The adaptive behavior under low-speed impact loads is ruled by the shear rate field in the liquid during the deformation. • FE simulations investigate the interaction between solid and liquid phases underlying increased mechanical properties. • Using a non-Newtonian filler leads to the best performance when compared with air- or other liquids-filled configurations. [ABSTRACT FROM AUTHOR]