Bending characteristics of carbon nanotubes: Micropolar elasticity models and molecular dynamics simulations

Abstract

The present paper aims at evaluating non-classical continuum parameters for each class of armchair and zigzag single-walled CNTs focusing on the scale effect in their flexural behavior observed in molecular dynamics (MD) simulations. Through a non-linear optimization approach, the bending rigidities obtained from atomistic simulations are compared to those derived from non-classical continua. For MD simulations, a novel method ensuring pure bending is introduced and for continuum modeling, micropolar, constrained micropolar, and modified couple stress theories are employed. The results reveal that adopted non-classical theories, notably micropolar theory, provide reasonable outcomes with an obvious failure of classical Cauchy theory.

Keywords:

• Micropolar continua
• molecular dynamics simulation
• size effect in bending modulus
• SWCNTs parameters identification
• optimization

Additional information

Funding

This work was done when Razie Izadi had a research scholarship at DISG, Sapienza University of Rome, with financial support of Italian Ministry of Education, University and Research, PRIN 2017, project 2017HFPKZY (Grant No. B86J16002300001) “Modeling of constitutive laws for traditional and innovative building materials” CUP: B88D19001130001, with Patrizia Trovalusci as Sapienza local PI. The support of Sapienza Research Grants “Progetti Medi” 2017 (Grant No. B83C17001440005) and “Progetti Grandi” 2018 (Protocol No. RG1181642E3B3117) are also acknowledged.