Evaluation of the Mechanical Parameters of Nanotubes by Means of Nonclassical Theories of Shells

In [3] the stiffness of bridges and cantilevers made of natural chrysotile asbestos nanotubes has been studied by means of scanning probe microscopy. The stiffness is defined as a ratio of the value of the local load (applied to the tube) to the value of the displacement. Nanotubes with different fillers are analyzed. Experiments show that the stiffness of the tube depends on the materials for filling. The tubes with water are softer and the tubes filled with mercury are more rigid than tubes without filling materials. It was shown in [3] that the classical theory of bending can not explain the experimental results, but the experimental results well agree with the Timoshenko-Reissner theory (at least qualitatively), when the interlaminar shear modulus of elasticity changes for different filling materials. When additional factors such as lamination of structure and cylindrical anisotropy are taken into account the theory of Rodionova-Titaev-Chernykh (RTC) permits to obtain much more reliable results. In this work the authors also applied another nonclassical shell theory, namely the shell theory of Paliy-Spiro (PS) developed for shells with moderate thickness. The comparison of nonclassical shell theories (RTCh and PS) with experimental data and FEM calculations are presented.