Buckling of Thin Cylindrical Shells Under Locally Elevated Compressive Stresses

Abstract

Thin cylindrical shells used in engineering applications are often susceptible to failure by elastic buckling. Most experimental and theoretical research on shell buckling relates only to simple and relatively uniform stress states, but many practical load cases involve stresses that vary significantly throughout the structure. The buckling strength of an imperfect shell under relatively uniform compressive stresses is often much lower than that under locally high stresses, so the lack of information and the need for conservatism have led standards and guides to indicate that the designer should use the buckling stress for a uniform stress state even when the peak stress is rather local. However, this concept leads to the use of much thicker walls than is necessary to resist buckling, so many knowledgeable designers use very simple ideas to produce safe but unverified designs. Unfortunately, very few scientific studies of shell buckling under locally elevated compressive stresses have ever been undertaken. The most critical case is that of the cylinder in which locally high axial compressive stresses develop extending over an area that may be comparable with the characteristic size of a buckle. This paper explores the buckling strength of an elastic cylinder in which a locally high axial membrane stress state is produced far from the boundaries (which can elevate the buckling strength further) and adjacent to a serious geometric imperfection. Care is taken to ensure that the stress state is as simple as possible, with local bending and the effects of internal pressurization eliminated. The study includes explorations of different geometries, different localizations of the loading, and different imperfection amplitudes. The results show an interesting distinction between narrower and wider zones of elevated stresses. The study is a necessary precursor to the development of a complete design rule for shell buckling strength under conditions of locally varying axial compressive stress.

Structural Behavior of Thin-Walled Metal Silos Subject to Different Flow Channel Sizes under Eccentric Discharge Pressures

“…18), which arises because the local flattening of the shell produces a much higher local radius of curvature (Rotter, 1985). This was also shown in the study of Rotter et al (2011). …”

Buckling of cylindrical metal shells on discretely supported ring beams

“…Published research to date on buckling of cylinders above local supports has focused on the simple cylindrical shell on discrete supports [16][17][18][19][20], which is a rare situation in practice. Conditions of localized elevated axial compression have also been studied [21][22][23], but these cannot be easily applied to the conditions above a ring beam. No specific explorations ever appear to have been conducted into cylindrical shell buckling in the practically important situation of a shell resting on a discretely supported ring beam.…”

Form of circumferential weld-induced imperfections for tapered-wall cylindrical shell structures

“…The applicability of these imperfection forms in cylinders with constant wall thickness has been studied extensively (e.g. Teng and Rotter 1992, Rotter 2004, Rotter et al 2011, Song et al 2004, Vanlaere et al 2009). However, most large cylindrical shells in practice are tapered-wall structures, and the applicability of the two forms for tapered-wall cylinders needs further study.…”