The use of virtual work for the formfinding of fabric, shell and gridshell structures

Christopher Williams, Paul Shepherd, Emil Adiels, Mats Ander, Erica Hörteborn, Jens Olsson, Karl-Gunnar Olsson, Alexander Sehlström

Research output: Contribution to conferencePaper

Abstract

The use of the virtual work theorem enables one to derive the equations of static equilibrium of fabric, shell and gridshell structures from the compatibility equations linking the rate of deformation of a surface to variations in its velocity. If the structure is treated as a continuum
there is no need to consider its micro-structure provided that the grid is fine compared to the overall geometry. Thus we can include fabrics, ribbed shells, corrugated shells and gridshells with a fine grid, such as
the Mannheim Multihalle. The equilibrium equations are almost identical to those obtained by assuming that a shell is thin and of uniform thickness, but are more general in their application. Our formulation introduces
the concept of geodesic bending moments which are relevant to gridshell structures with continuous laths.
The virtual work theorem is more general than the energy theorems, which it includes as a special case. Hence it can be applied to surfaces which admit some form of potential, including minimal surfaces
and hanging fabrics. We can then use the calculus of variations for the minimization of a surface integral to define the form of a structure.
Many existing formfinding techniques can be rewritten in this way, but we concentrate on surfaces which minimize the surface integral of the mean curvature subject to a constraint on the enclosed volume, producing a surface of constant Gaussian curvature. This naturally leads to the more general study of conjugate stress and curvature
directions, and hence to quadrilateral mesh gridshells with flat cladding panels and no bending moments in the structural members under own weight.
Original languageEnglish
Pages286 – 315
Number of pages29
Publication statusPublished - 24 Sep 2018
EventAdvances in Architectural Geometry - Chalmers University of Technology, Gothenburg, Sweden
Duration: 24 Sep 201825 Sep 2018
http://www.architecturalgeometry.org/aag18/

Conference

ConferenceAdvances in Architectural Geometry
Abbreviated titleAAG2018
CountrySweden
CityGothenburg
Period24/09/1825/09/18
Internet address

Keywords

  • Virtual work
  • fabric, shell and gridshell structures
  • calculus of variations
  • conjugate directions

Cite this

Williams, C., Shepherd, P., Adiels, E., Ander, M., Hörteborn, E., Olsson, J., ... Sehlström, A. (2018). The use of virtual work for the formfinding of fabric, shell and gridshell structures. 286 – 315. Paper presented at Advances in Architectural Geometry, Gothenburg, Sweden.