Shell structures

Behaviour and design of shell structures

Shells are thin curved structures formed from two-dimensional surfaces.  The simplest shell forms are cylinders, cones and spheres.  The behaviour of these structures is considerably more complex than that of beams, frames and plates, and they are susceptible to a wide variety of different failure modes by buckling, plastic collapse and rupture.

The research in this area explores two aspects. First it examines generic features of the behaviour, analysis and design procedures for shell structures and their codification into national and international standards.

Second it explores the detailed behaviour of specific shells under conditions that arise in practical structural engineering construction.

Much of the research is focussed on answering key questions encountered in the development of the world’s first complete standard on the strength and stability of shells, which has been developed under the convenorship of, is edited by, Prof. Michael Rotter.

Generic research and the design of shell structures

  • Formulation of general design procedures for shells
  • Numerical analyses of different types and their interpretation in shell design processes
  • Development of the European Standard (EN 1993-1-6) on the Strength and Stability of Shell Structures
  • Imperfection measurement and characterisation
  • Tolerances and their effect on design processes and strength specifications
  • Elastic-plastic interaction buckling in shells

 

Specific problems in shell behaviour and design

  • Buckling of cylinders under axial compression and internal pressure with different imperfection forms
  • Elephant’s foot buckling in cylinders
  • Buckling of cylinders with locally elevated axial compressive stresses
  • Buckling and collapse of cylinders under local loads normal to the shell
  • Cylinders supported at discrete points (brackets and local supports)
  • Silo cylinders under solids flow eccentric discharge pressures
  • Cylinder-cone intersections at the transition in silos
  • Strength of silo conical hoppers
  • Buckling and collapse of conical roof structures
  • Ring stiffener and boundary constraint design requriements to permit shell buckling strengths to be achieved
  • Strength of silo shells under seismic actions
  • Corrugated shell construction and orthotropic stiffened shell design procedures