Anisotropic behaviors of helically corrugated cylindrical shells: Stress distributions and edge effects

摘要

This paper presents a stress analysis of helically corrugated cylindrical shells subjected to three elementary types of deformation loading, that is, axial elongation, axial torsion, and radial expansion. This study complements the work of the authors, in which the homogenized in-plane stiffness components and coupling stiffness coefficients of novel thin-walled structures possessing sinusoidal corrugating patterns have been investigated. In this study, the stress distribution in a representative unit cell element is computed using the finite-element method (FEM) with ABAQUSTM. A variety of FEM models are automatically created according to four groups of dimensionless parameters: ratio of radius to thickness, ratio of radius to corrugating depth, helical angle, and waveform number (thread). The simulation results provide fundamental insights into the effects of the various corrugation patterns on the von Mises stress developed in corrugated curved structures, including periodic stress distributions and irregular stress fluctuations in the vicinity of the edges. Peculiar and unprecedented stress characteristics are encountered at some specific geometries, indicating that the structures exhibit significant anisotropic sensitivity when compared to perfectly round cylindrical shell counterparts with zero amplitude of corrugation. A characteristic distance corresponding to the edge effect region, the so-called boundary layer length, is quantitatively identified in terms of the various geometric dimensionless parameters.