Synergistic Energy Absorption Mechanisms of Architected Liquid Crystal Elastomers. Issue 14 (1st March 2022)

• Record Type: Journal Article
• Authors: Jeon, Seung‐Yeol; Shen, Beijun; Traugutt, Nicholas A.; Zhu, Zeyu; Fang, Lichen; Yakacki, Christopher M.; Nguyen, Thao D.; Kang, Sung Hoon
• Is Part Of: Advanced materials. Volume 34:Issue 14(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-01
• Subjects: energy absorption -- liquid crystal elastomers -- metamaterial -- power‐law relation -- stacking effect -- viscoelasticity; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202200272
• Languages: English
• ISSNs: 0935-9648

Abstract

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. Abstract : A unique rate‐dependent energy absorption behavior of architected materials based on liquid crystal elastomers is reported. The synergistic interaction between viscoelastic dissipation and snap‐through buckling causes the energy absorption density to increase with strain rate according to a power‐law relationship and with a number of layers for multilayered structures. The study can contribute to the development of lightweight extreme energy‐absorbing metamaterials.