Topologically Optimised Cast Glass Grid Shell Nodes

Abstract

Cast glass is a promising structural material that has seen increasing use in the build environment over the last year. It offers a great freedom of shape for designers and engineers, beyond the two-dimensional float glass that is still primarily used. Despite this, cast glass in practice has only been used for solid bricks, mimicking traditional ceramic brickwork. Little exploration has been made on the complex shapes that can be achieved in cast glass. One of the largest challenges of cast glass is its slow and meticulous cooling process required after casting, to prevent the occurrence of internal stresses. This costly annealing process is the main limitations for producing large scale cast glass elements in an affordable way. Experience in large scale solid glass mirror castings performed for NASA show that annealing times can be reduced through smart design.
Structural topology optimisation is a design tool for creating light-weight, material efficient elements. Its application has mostly been limited to industrial and aerospace design, though it is slowly being introduced in the built environment as the additive manufacturing required for these geometries becomes more advanced, and affordable. So far, topology optimisation of cast glass design has remained unexplored. The goal of this thesis is to investigate the potential of using topology optimisation as a design tool for complex structural cast-glass elements with a reduced annealing time. For this, a complex-shaped grid shell has been redesigned in glass, using optimised cast glass nodes. The entire fabrication process, from digital design, to physical fabrication using additive manufacturing has been explored.