Synergistic Energy Absorption Mechanisms of Architected Liquid Crystal Elastomers

Abstract

A unique rate‐dependent energy absorption behavior of liquid crystal elastomer (LCE)‐based architected materials is reported. The architected materials consist of repeating unit cells of bistable tilted LCE beams sandwiched between stiff supports. The viscoelastic behavior of the LCE causes the energy absorption to increase with strain rate according to a power‐law relationship, which can be modulated by changing the degree of mesogen alignment and the loading direction relative to the director. For a strain rate of 600 s−1, the unit cell exhibits up to a 5 MJ m−3 energy absorption density, which is two orders of magnitude higher than the same structure fabricated from poly(dimethylsiloxane) elastomer and is comparable to the dissipation from irreversible plastic deformation exhibited by denser metals. For a multilayered structure of unit cells, nonuniform buckling of the different layers produces additional viscoelastic dissipation. This synergistic interaction between viscoelastic dissipation and snap‐through buckling causes the energy absorption density to increase with the number of layers. The sequence of cell collapse can be controlled by grading the beam thickness to further promote viscous dissipation and enhance the energy absorption density. It is envisioned that the study can contribute to the development of lightweight extreme energy‐absorbing metamaterials.

Advances in 4D printing of liquid crystalline elastomers: materials, techniques, and applications

“…Jeon et al recently reported that the energy absorption density of architected LCE materials increases with strain rate according to power-law relationship. 211 With this newly obtained knowledge, they achieved a 5 MJ m À3 energy absorption density at a strain rate of 600 s À1 , which is two orders of magnitude higher than previously reported results.…”

Neurotrauma Prevention Review: Improving Helmet Design and Implementation

“…Impressio’s helmet prototype contains liquid crystal elastomers housed within 3D printed columns [ 71 , 74 ]. Liquid crystal elastomers combine the self-organization of the liquid crystalline phase with the elasticity of an elastomer, offering an innovative and potentially superior approach to absorbing impact energy [ 75 – 77 ]. All three companies incorporated 3D printing into their design with an increased focus on the customization of helmet fit for each individual.…”

Neurotrauma Prevention Review: Improving Helmet Design and Implementation

“…77,80 Liquid crystal elastomers combine the self-organization of the liquid crystalline phase with the elasticity of an elastomer, offering an innovative and potentially superior approach to absorbing impact energy. [81][82][83] All three companies incorporated 3D printing into their design with an increased focus on the customization of helmet fit for each individual. Experimental evaluation is ongoing.…”