Stiffener Insertion Based Variance in Radial Stiffness of Multi-Concentric Hollow Tubes

Abstract

Shell theory solutions for radial buckling of multiply-concentric hollow cylinders are presented. Multicylindrical systems are those composed of two or more concentically mounted hollow tubes, wherein the annular space mediates inter-tube forces, attractive or repulsive depending on structural details of composites. Reflecting the multiple core-shell structures, the systems often exhibit peculiar radial buckling modes, which should be relevant to macro scale applications for deep water oil and gas transportation andmicroscale realization in lipid bilayer tubes. In this article, we focus on an illustrative example of such the multiplytubular systems with nanometric dimension, the so-called multiwalled carbon nanotubes (MWNTs). Theoretical analysis based on a thin shell theory allows us to find anomalous radial buckling behaviors of MWNTs driven by hydrostatic pressure. The obtained buckling modes are characterized by petal-like wavy cross sections, which is what we call the radial corrugation of MWNTs. An important observation is the mechanical consequence of stiff core-tube insertion into the innermost hollow region of a given MWNT. The insertion results in a significant variance in the critical buckling pressure, above which the MWNT undergoes radial corrugation. The insertion-induced-variance in the critical pressure is due to the primary role of inter-tube interaction between adjacent constituent tubes, as explained within our theoretical model.

Kaleidoscopic Mode Change in Cross-Sectional Deformation of Reinforced Carbon Nanotubes

“…[26][27][28][29][30] Insertion of these foreign materials results in radial stiffness enhancement of the innermost tube, thus gives rise to change in the corrugation modes as we previously demonstrated. 31 Against the backdrop, it is interesting to consider the combinatorial effects on the corrugation modes of MWNT, i.e., what mode patterns can be obtained in the presence of both the surrounding elastic medium and the stiffner insertion in the core cavity.…”