17 2022 2021-12-15 10.1002/pssr.202100415 A bundle of aligned carbon nanotubes (CNTs) under lateral loading and heating is considered under plane strain conditions within the framework of a molecular dynamics model with a reduced number of degrees of freedom. Bundles of CNTs of sufficiently large diameter exhibit negative lateral thermal expansion. The coefficient of thermal expansion is practically constant up to a temperature of 1500 K and practically does not depend on biaxial lateral compression up to a volumetric compressive strain of 0.06. This anomalous behavior is explained by the two mechanisms: elliptization of the CNT cross section and bending of the CNT walls by thermal fluctuations. Elliptization leads to a decrease in the cross-sectional area of the CNT, and the bending of the CNT wall leads to a decrease in the effective diameter of the CNT. A bundle with CNTs of the largest investigated diameter demonstrates a large negative coefficient of linear thermal expansion, (Formula presented.) K−1, which is weakly dependent on temperature. © 2021 Wiley-VCH GmbH https://repo.bashgmu.ru/publication/3961 https://repo.bashgmu.ru/files/4137