# Optimization-based approach to the calibration of mesoscale mechanical models for carbon nanotube systems

## TL;DR

This paper introduces a new mesoscale mechanical model for carbon nanotubes based on an enhanced vector model, calibrated through an optimization approach to match atomistic simulations, enabling accurate simulations of CNTs of various lengths.

## Contribution

The paper presents a novel calibration method for a mesoscale CNT model using optimization, linking atomistic data with mesoscale parameters.

## Key findings

- Stiffness parameters become length-independent after a critical CNT length.
- Calibrated parameters closely match atomistic simulation results.
- Model effectively describes elastic interactions in CNTs across different lengths.

## Abstract

A new mesoscale mechanical model, describing elastic interactions in carbon nanotubes (CNT) and other nanofilaments, is proposed. Functional form of the developed model is based on enhanced vector model (EVM) that describes basic types of bond deformations: tension, torsion, bending and shear. Calibration of bond stiffnesses is performed by adjusting EVM parameters to reproduce both CNT's deformation energies and shape observed in a full-atomistic simulation. The parameters obtained are compared with the ones obtained from Euler-Bernoulli beam theory considerations. It is found that after certain critical length of a tested CNT specimen its stiffness parameters become length-independent and can be used in mesoscale simulations of CNTs of arbitrary length.