A comparative study of two molecular mechanics models based on harmonic potentials

Junhua Zhao, Lifeng Wang, Jin Wu Jiang, Zhengzhong Wang, Wanlin Guo, Timon Rabczuk

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


We show that the two molecular mechanics models, the stick-spiral and the beam models, predict considerably different mechanical properties of materials based on energy equivalence. The difference between the two models is independent of the materials since all parameters of the beam model are obtained from the harmonic potentials. We demonstrate this difference for finite width graphene nanoribbons and a single polyethylene chain comparing results of the molecular dynamics (MD) simulations with harmonic potentials and the finite element method with the beam model. We also find that the difference strongly depends on the loading modes, chirality and width of the graphene nanoribbons, and it increases with decreasing width of the nanoribbons under pure bending condition. The maximum difference of the predicted mechanical properties using the two models can exceed 300% in different loading modes. Comparing the two models with the MD results of AIREBO potential, we find that the stick-spiral model overestimates and the beam model underestimates the mechanical properties in narrow armchair graphene nanoribbons under pure bending condition.

Original languageEnglish
Article number063509
JournalJournal of Applied Physics
Issue number6
Publication statusPublished - 2013 Feb 14

Bibliographical note

Funding Information:
We gratefully acknowledge support by the Germany Science Foundation and the National Natural Science Foundation of China. The authors would like to thank Professor T. C. Chang and Dr. M. Silani for many useful discussions.

ASJC Scopus subject areas

  • General Physics and Astronomy


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