On the elastic rod models for mechanical tests of one-dimensional nanostructures under transverse loads

Quantifying the intrinsic mechanical properties of one-dimensional nanostructures such as nanotubes and nanowires is technically challenging due to their extremely small sizes and large aspect ratios. In comparison with direct tensile measurements, displacement responses of an end-clamped rod under...

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Veröffentlicht in:Journal of applied physics 2020-10, Vol.128 (16)
Hauptverfasser: Wang, Shijun, Xu, Zhiping
Format: Artikel
Sprache:eng
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Zusammenfassung:Quantifying the intrinsic mechanical properties of one-dimensional nanostructures such as nanotubes and nanowires is technically challenging due to their extremely small sizes and large aspect ratios. In comparison with direct tensile measurements, displacement responses of an end-clamped rod under transverse loads are more significant and more feasible for experimental characterization. However, the displacement–force relationship could be non-trivial due to the presence of geometrical nonlinearity and contributions from both stretching and bending. Choosing a simple but reliable model to extract the mechanical parameters from experimental data is thus important for the design of tests. Starting from the fully nonlinear, extensible Kirchhoff rod theory, we explore the application scope of several simplifications by referring to recent experimental studies on carbon nanotubes. The horizontal displacement is shown to be crucial information for strain analysis in the stretching-dominated regime, and the constant-tension assumption fails at large loading amplitudes. The capability of several simplified models is assessed through the Euclidean distance between deflection curves, as well as the error in estimating the strain distribution. Practical issues such as boundary slippage and dynamical effects are also discussed. This study offers a theoretical groundwork to understand the mechanical responses of one-dimensional nanostructures in typical experimental setups and provides a standard or guideline for the experimental design.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0030366