Xavier Tellier

From mesh to structure : fabrication-aware design of architectural envelopes

Advisors: Olivier Baverel (NAVIER), Laurent Hauswirth (LAMA), Cyril Douthe (NAVIER)

Started january 2017

Summary of the project

The thesis work is centered on meshes with planar faces and offset, i.e. meshes that admit a parallel mesh. The existence of an offset is of particular interest for the fabrication of gridshells. First of all, an offset insures that each beam connection can be given an axis. This axis facilitates significantly the fabrication of the connections. Secondly, some offsets have the additional property of lying at constant distance from the mesh. This property eases significantly the fabrication of multilayers structures. ‘Constant distance’ can have three different meanings, which each yield a remarkable class of offsets:

• Meshes with vertex offset, also referred to as circular meshes, offer a great variety of shape;
• Meshes with edge offset can be built with perfect nodes;
• Meshes with face offset, also called conical mesh, are particularly suited for panelized freeform envelopes.

A discretization of surfaces with constant mean curvature (CMC) is being developed. CMC surfaces have many interesting properties for use as a shape for an architectural envelope: First, they can be fitted on any boundary, which make them suitable for applications such as covering courtyards. Secondly, they are aesthetically pleasing, as they take the harmonious shape of an inflated soap bubble. Our discretization offers the following additional properties:

• Planar quadrangular faces;
• Orthotropic edge offset;
• Good mechanical properties under normal pressure loading.

A second topic is the rationalization of the beam-panel link in gridshells. A new family of mesh has been identified for this purpose. It offers interesting applications for the fabrication of doubly-curved metallic façade and discrete shells made of sandwich panels.

Another axis of research is surfaces with planar curvature lines. A discretization of these surfaces by circular meshes has been developed. The resulting meshes have interesting fabrication and mechanical properties. An intuitive design method is proposed.

Publications

[1] Tellier, X., Baverel, O., Douthe C., Hauswirth, L. 2018, Gridshells without kink angle between beams and cladding panels, IASS Symposium 2018

[2] Tellier, X., Hauswirth, L., Baverel, O., Douthe C., 2018, Discrete CMC surfaces for doubly curved building envelopes, Advances in Architectural Geometry – Symposium 2018