Elastic Systems for Compliant Shading Enclosures

Abstract

Forces are everywhere, in and on every object. They even act in ‘empty space’. Forces form objects, hold them together or destroy them. Forces act within atoms, molecules, and gases, in liquids and in solid bodies. Frei Otto. Krafte, die Objekte bilden. This study investigates elastic structures and materials in terms of mechanical and physical properties for the design of a bistable (capacitor) mechanism which is programmed to deform an aperture, complying to variable thermal loads and light to provide shade and thermal comfort regulation between an exterior and interior space. Elastic properties, precedents and materials are studied and modeled to identify the maximum stress and strain force by which materials and structures are capable of deforming and returning to an original size and shape without permanent deformation. Bistable structural mechanisms, organized with elastic spring steel strips and pin connections, in the form of an aperture, are then investigated as a capacitor. The capacitor utilizes prestressed structural strips which deform an aperture with activated thermostat coils through diurnal thermal loads from the sun. The increasing storage of elastic strain energy is programmed to rotate and close the aperture at a maximum stressed position, at which point, it is capable of releasing the stored kinetic energy with a decrease in heat input, triggering the mechanism to open the aperture instantly. The arrangement of the self adjusting shade system is organized and manipulated spatially through a variety of prototype developments as a passive glass enclosure for the east and west facades of buildings. The University of Arizona’s entry for the Department of Energy’s Solar Decathlon Competition is used as a testing platform for the final prototype, validating its performance, function and value as a potential building component.