Large-deformation elastic hardening of a structured graphene kirigami nano-spring with re-entrant honeycombs

HC Feng and K Cai and J Shi, COMPUTATIONAL MATERIALS SCIENCE, 244, 113180 (2024).

DOI: 10.1016/j.commatsci.2024.113180

The programmable nature of graphene kirigami enables it highly applicable in the development of stretchable nanodevices. In this study, we employed molecular dynamics simulations to investigate the large deformation behavior of a structured graphene kirigami nano-spring (GKNS) with re-entrant honeycombs. During a uniaxial test, the elastic deformation can be categorized into two stages based on the applied load level. Stage I exhibits a maximal strain (aYstart) exceeding 50 % under low loading conditions, while stage II demonstrates a strain (aYend) surpassing 70 % at a high hardening rate. Both aYstart and aYend are greater than those observed in GKNS with transversal periodic boundary conditions. Furthermore, increasing the length or decreasing the width of bars within GKNS with cells of identical shape leads to an increase in both aYstart and aYend values. Ambient temperature has minimal impact on aYstart and aYend however, higher temperatures result in lower hardening rates due to weakened carbon-carbon bonds within GKNS structures. Additionally, variations in cell/void arrangement within structured GKNS affect both aYstart and aYend values, whereas widening the GKNS structure leads to reduced hardening rates. The findings presented herein provide valuable insights for designing nanodevices that necessitate significant deformations.

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