Form-finding of grid shells with continuous elastic rods

Abstract

Grid shells with continuous elastic rods have the advantages to generate curved spaces with uniform members and joints. However, finding the boundary conditions, including the grid pattern and bearing positions, which lead to a specific geometry, is not an easy task. Designers have to keep equal grid lengths, minimise the residual forces and ensure the smoothness of geometries simultaneously. In this paper, we present a new numerical method which can derive the grid pattern and bearing positions in accordance with a desired geometry. This is done by finding the least strain energy state of the elastic grid in the solution domain defined by constraints. This method can provide architects a grid pattern that satisfies all the geometrical demands. At the same time, a structure with less strain energy is favoured by engineers. This is especially important for elastic grid shells, whose structural stability is largely affected by the residual forces.