Mechanical behavior and fracture mechanisms of single-, double-, and triple-walled carbon nanotubes under tensile strain: A molecular dynamics study

Abstract

Carbon nanotubes (CNTs) exhibit exceptional mechanical attributes, including high tensile strength and elastic modulus, positioning them as prime constituents for advanced nanocomposite systems. This study presents a comprehensive molecular dynamics investigation into the elastic behavior of single-walled and multi-walled CNTs with n = 1, 2, 3 walls in their pristine state, free of structural defects. We simulate uniaxial tensile loading to evaluate the elastic modulus and mechanical response of CNTs under controlled conditions. This study investigates the elastic behavior using molecular dynamics simulations, revealing distinct equilibration dynamics with total energy stabilizing at 1.875eV, 3.91eV, and 6.18eV, respectively, over 0.2–0.5ns. Further, mean squared displacement was evaluated, which offers an atomic-scale perspective on stability of the structure under Tersoff potential. Stress–strain curves are plotted and, revealed that the single-walled, double-walled, and triple-walled CNTs sustain maximum stress values of approximately 60GPa, 110GPa, and 130GPa, respectively. The findings predicted that the pristine MWCNTs exhibit a higher Young’s modulus and an extended elastic range, confirming their superior mechanical integrity. Additionally, we examine the fracture mechanics by comparing atomistic deformations developed during strain in single-walled and multi-walled CNTs. This study delineates the structural influences on the tensile strength and elasticity of defect-free CNTs, establishing a baseline mechanical characterization for subsequent investigations into defect-mediated effects and bio-nanoengineering applications. © 2025 Elsevier B.V., All rights reserved.