MESONT is a LAMMPS package for simulation of nanomechanics of carbon nanotubes (CNTs). The model is based on a coarse-grained representation of CNTs as "flexible cylinders" consisting of a variable number of segments. Internal interactions within a CNT and the van der Waals interaction between the tubes are described by a mesoscopic force field designed and parameterized based on the results of atomic-level molecular dynamics simulations. The description of the force field is provided in the papers listed below. -- This package was created by Maxim Shugaev (mvs9t@virginia.edu) at the University of Virginia. The Fortran library implementing basic level functions describing stretching, bending, and intertube components of the mesoscopic CNT force field, used by this package is developed by Alexey N. Volkov (avolkov1@ua.edu) at the University of Alabama. -- The following commands are contained in this package: atom_style mesont This command enables mesont atom_style containing variables used for further commands in MESONT. pair_style mesont/tpm cut table_path BendingMode TPMType This command activates a pair_style describing CNT mesoscopic tubular potential model (TPM) force field. "cut" is cutoff distance that should be set to be at least max(2.0*L, sqrt(L^2/2 + (2.0*R + Tcut)^2)), where L is the maximum segment length, R is the maximum tube radius, and Tcut = 10.2 A is the maximum distance between surfaces of interacting segments. However, the recommended cutoff is 3L. compute mesont This command allows evaluation of per atom and total values of stretching, bending, and intertube interaction components of energies. Use the following flags: 'estretch', 'ebend', 'etube'. -- References: L. V. Zhigilei, C. Wei, and D. Srivastava, Mesoscopic model for dynamic simulations of carbon nanotubes, Phys. Rev. B 71, 165417, 2005. A. N. Volkov and L. V. Zhigilei, Structural stability of carbon nanotube films: The role of bending buckling, ACS Nano 4, 6187-6195, 2010. A. N. Volkov, K. R. Simov, and L. V. Zhigilei, Mesoscopic model for simulation of CNT-based materials, Proceedings of the ASME International Mechanical Engineering Congress and Exposition (IMECE2008), ASME paper IMECE2008-68021, 2008. A. N. Volkov and L. V. Zhigilei, Mesoscopic interaction potential for carbon nanotubes of arbitrary length and orientation, J. Phys. Chem. C 114, 5513-5531, 2010. B. K. Wittmaack, A. H. Banna, A. N. Volkov, L. V. Zhigilei, Mesoscopic modeling of structural self-organization of carbon nanotubes into vertically aligned networks of nanotube bundles, Carbon 130, 69-86, 2018. B. K. Wittmaack, A. N. Volkov, L. V. Zhigilei, Mesoscopic modeling of the uniaxial compression and recovery of vertically aligned carbon nanotube forests, Compos. Sci. Technol. 166, 66-85, 2018. B. K. Wittmaack, A. N. Volkov, L. V. Zhigilei, Phase transformation as the mechanism of mechanical deformation of vertically aligned carbon nanotube arrays: Insights from mesoscopic modeling, Carbon 143, 587-597, 2019. A. N. Volkov and L. V. Zhigilei, Scaling laws and mesoscopic modeling of thermal conductivity in carbon nanotube materials, Phys. Rev. Lett. 104, 215902, 2010. A. N. Volkov, T. Shiga, D. Nicholson, J. Shiomi, and L. V. Zhigilei, Effect of bending buckling of carbon nanotubes on thermal conductivity of carbon nanotube materials, J. Appl. Phys. 111, 053501, 2012. A. N. Volkov and L. V. Zhigilei, Heat conduction in carbon nanotube materials: Strong effect of intrinsic thermal conductivity of carbon nanotubes, Appl. Phys. Lett. 101, 043113, 2012. W. M. Jacobs, D. A. Nicholson, H. Zemer, A. N. Volkov, and L. V. Zhigilei, Acoustic energy dissipation and thermalization in carbon nanotubes: Atomistic modeling and mesoscopic description, Phys. Rev. B 86, 165414, 2012. A. N. Volkov and A. H. Banna, Mesoscopic computational model of covalent cross-links and mechanisms of load transfer in cross-linked carbon nanotube films with continuous networks of bundles, Comp. Mater. Sci. 176, 109410, 2020.