DESIGN AND ANALYSIS OF A DEPLOYABLE PROGRAMMABLE ORIGAMI STRUCTURE

Abstract

Adaptive façades hold the potential of enabling buildings to interact with the energy fluxes as opposed to isolate their interior from the outside influence. This change in the relationship between buildings and their environment can improve the energy efficiency of buildings and improve the sustainability of the built environment. This thesis examines a proposed deployable programmable origami structure that can be used as a smart sun shading device. The proposed design is that of a tetrakis tiling, in which the surface is tessellated with right angle triangular tiles. The edges between all adjacent tiles are actuated using shape memory alloy (SMA) wires controlled through an Arduino board to create a folding angle between the tiles. Despite the simplicity and regularity of the tiling geometry, the number of theoretically possible configurations starting from a flat sheet increases exponentially with the number of actuated edges, being able to achieve complex geometries. In order to assess the feasibility of such a design, this thesis presents an experimental and a numerical study using different number of tiles and tile materials. All the numerical simulations are done using a dynamic relaxation algorithm implemented in MATLAB. The study of a single 2 tiles module focuses on the dependency of the folding angle between the two tiles on the actuating current. Both experimental and numerical simulation results are presented for two types of tile materials: paper prototypes which best approximate the model used in numerical simulations and acrylic prototypes, which is a likely candidate for use in deployable structures. The 8 tiles system is examined from the point of view of the possible distinct configurations. For a subset of 14 chosen configurations, the deflection and shaded area are measured experimentally and simulated numerically for both the paper and the acrylic prototypes. An assessment of the power consumption, sun shading performance and maximum deflections is made. The thesis concludes with a preliminary study of a 32 tiles acrylic model that highlights some of the most important challenges and likely strategies for scaling up of the physical prototype.