科研之友
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摘要
The buckling behaviours of boron nanotubes (BNTs) are investigated in this paper by using molecular structural mechanics (MSM) simulations and elastic shell models. Two types of BNTs (alpha and chi-BNTs) whose structures are proven to be thermally stable in first-principles molecular dynamics simulations are considered in the study. Our MSM results show a shell-to-column buckling mode transition occurring in BNTs with increasing aspect ratio. The critical buckling force of the column buckling of long BNTs significantly decreases as the aspect ratio grows, while that of the shell buckling of short BNTs is almost independent of the aspect ratio. MSM simulations also show that alpha and chi-BNTs both have anisotropic elastic properties. As a result, the simple Donnell shell model previously employed in other tubular nanomaterials becomes inapplicable in describing the buckling behaviours of the present BNTs. Under this circumstance, we propose an orthotmpic elastic shell model to consider the anisotropy of elastic properties in the continuum mechanical modelling of BNTs. Through the orthotropic elastic shell model, the buckling behaviours of alpha and chi-BNTs are found to have different relations with their chirality, which is attributed to different anisotropy features observed in the elastic properties of these two BNTs.
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单位harbin inst technol
