Imperfection sensitivity in cylindrical shells under uniform bending
| Autor: | Adam J. Sadowski, O. Kunle Fajuyitan |
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| Rok vydání: | 2018 |
| Předmět: |
Technology
Engineering Civil Materials science Structural system 020101 civil engineering 02 engineering and technology Bending finite element analysis Turbine Civil Engineering 0905 Civil Engineering 0201 civil engineering Engineering 0203 mechanical engineering TUBES ovalisation in cylindrical shells LENGTH Boundary value problem Sensitivity (control systems) Algebraic number uniform bending Civil and Structural Engineering automation Science & Technology business.industry 1202 Building Building and Construction Function (mathematics) Structural engineering FLEXURE Finite element method nonlinear buckling 020303 mechanical engineering & transports ELASTIC CYLINDERS Construction & Building Technology business imperfection sensitivity STEEL SILOS BEHAVIOR NONLINEAR STABILITY |
| Popis: | Efforts are ongoing to characterise a comprehensive resistance function for cylindrical shells under uniform bending, a ubiquitous structural system that finds application in load-bearing circular hollow sections, tubes, piles, pipelines, wind turbine support towers, chimneys and silos. A recent computational study by Rotter et al. demonstrated that nonlinear buckling of perfect elastic cylinders under bending is governed by four length-dependent domains –‘short’, ‘medium’, ‘transitional’ and ‘long’– depending on the relative influence of end boundary conditions and cross-sectional ovalisation. The study additionally transformed its resistance predictions into compact algebraic relationships for use as design equations within the recently developed framework of reference resistance design. This article extends on the above to present a detailed computational investigation into the imperfection sensitivity of thin elastic cylindrical shells across the most important length domains, using automation to carry out the vast number of necessary finite element analyses. Geometric imperfections in three forms – the classical linear buckling eigenmode, an imposed cross-sectional ovalisation and a realistic manufacturing ‘weld depression’ defect – are applied to demonstrate that imperfection sensitivity is strongly length dependent but significantly less severe than for the closely related load case of cylinders under uniform axial compression. The axisymmetric weld depression almost always controls as the most deleterious imperfection. The data are processed computationally to offer an accurate yet conservative lower-bound algebraic design characterisation of imperfection sensitivity for use within the RRD framework. The outcomes are relevant to researchers and designers of large metal shells under bending and will appeal to computational enthusiasts who are encouraged to adopt the automation methodology described herein to explore other structural systems. |
| Databáze: | OpenAIRE |
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